Counties in Illinois with the fastest-rising temperatures in the last 100 years
Written by:
January 3, 2023
tradville // Shutterstock
Counties in Illinois with the fastest-rising temperatures in the last 100 years
Hitting 116 degrees F in normally temperate Portland, Oregon. 105 degrees in Reno in September, just as summer is meant to be waning. And in California's Death Valley National Park, temperatures hit almost 130 degrees in the aptly named Furnace Creek, marking a world record for the hottest September day in history.
2021 and 2022 saw some of the hottest temperatures ever recorded, as across the country extreme heat waves wreaked havoc on communities accustomed to more moderate weather. For many regions, the consequences were grave: in the 2021 Western heatwave, hundreds lost their lives, largely due to a lack of air conditioning, and wildfires ravaged the area.
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Map of the past year's temperatures compared to the 100-year average
While not every county in the nation has experienced such extreme heat, climate change has dramatically changed the heat landscape in nearly every state. Coastal regions and the Southern U.S. are particularly vulnerable to rising temperatures, and are also frequently targets of extreme weather events like hurricanes and tornadoes.
Just as all states are not impacted equally by rising temperatures, regions within states have also seen widely different temperature changes over the last decades. Factors such as proximity to urban areas, bodies of water, and mountains can dramatically change the climate of a region. Stacker cited data from the National Oceanic and Atmospheric Administration's National Center for Environmental Information to identify the counties in Illinois with the greatest departure from average temperatures during the period December 2021 to November 2022 compared to the 1901-2000 average. Average temperature over the past year served as a tiebreaker. Additional data on recent average high and low temperatures for each county is also included.
#50. Randolph County
- Average temperature, Dec. 2021-Nov. 2022: 56.5 degrees Fahrenheit (1.3 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 45.6 F (1.5 F above century average)
- Recent average high: 67.5 F (1 F above century average)
- #27 warmest year since 1895
- Recent average low: 45.6 F (1.5 F above century average)
- Recent average high: 67.5 F (1 F above century average)
#49. Franklin County
- Average temperature, Dec. 2021-Nov. 2022: 56.6 degrees Fahrenheit (1.3 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 45.5 F (1.3 F above century average)
- Recent average high: 67.6 F (1.3 F above century average)
- #23 warmest year since 1895
- Recent average low: 45.5 F (1.3 F above century average)
- Recent average high: 67.6 F (1.3 F above century average)
#48. Saline County
- Average temperature, Dec. 2021-Nov. 2022: 57 degrees Fahrenheit (1.3 F above 1901-2000 average)
- #28 warmest year since 1895
- Recent average low: 46.2 F (1.2 F above century average)
- Recent average high: 67.9 F (1.4 F above century average)
- #28 warmest year since 1895
- Recent average low: 46.2 F (1.2 F above century average)
- Recent average high: 67.9 F (1.4 F above century average)
#47. Union County
- Average temperature, Dec. 2021-Nov. 2022: 57.1 degrees Fahrenheit (1.3 F above 1901-2000 average)
- #26 warmest year since 1895
- Recent average low: 46.1 F (1.2 F above century average)
- Recent average high: 68.1 F (1.3 F above century average)
- #26 warmest year since 1895
- Recent average low: 46.1 F (1.2 F above century average)
- Recent average high: 68.1 F (1.3 F above century average)
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#46. Johnson County
- Average temperature, Dec. 2021-Nov. 2022: 57.2 degrees Fahrenheit (1.3 F above 1901-2000 average)
- #28 warmest year since 1895
- Recent average low: 46.4 F (1.2 F above century average)
- Recent average high: 68.1 F (1.3 F above century average)
- #28 warmest year since 1895
- Recent average low: 46.4 F (1.2 F above century average)
- Recent average high: 68.1 F (1.3 F above century average)
#45. Stephenson County
- Average temperature, Dec. 2021-Nov. 2022: 48.1 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #29 warmest year since 1895
- Recent average low: 37.9 F (1.6 F above century average)
- Recent average high: 58.3 F (1.2 F above century average)
- #29 warmest year since 1895
- Recent average low: 37.9 F (1.6 F above century average)
- Recent average high: 58.3 F (1.2 F above century average)
#44. Carroll County
- Average temperature, Dec. 2021-Nov. 2022: 48.7 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #31 warmest year since 1895
- Recent average low: 38.7 F (1.7 F above century average)
- Recent average high: 58.7 F (1 F above century average)
- #31 warmest year since 1895
- Recent average low: 38.7 F (1.7 F above century average)
- Recent average high: 58.7 F (1 F above century average)
#43. Ogle County
- Average temperature, Dec. 2021-Nov. 2022: 49 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #29 warmest year since 1895
- Recent average low: 38.7 F (1.4 F above century average)
- Recent average high: 59.2 F (1.5 F above century average)
- #29 warmest year since 1895
- Recent average low: 38.7 F (1.4 F above century average)
- Recent average high: 59.2 F (1.5 F above century average)
#42. Whiteside County
- Average temperature, Dec. 2021-Nov. 2022: 49.9 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 39.6 F (1.4 F above century average)
- Recent average high: 60.1 F (1.4 F above century average)
- #27 warmest year since 1895
- Recent average low: 39.6 F (1.4 F above century average)
- Recent average high: 60.1 F (1.4 F above century average)
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#41. Grundy County
- Average temperature, Dec. 2021-Nov. 2022: 50.6 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #28 warmest year since 1895
- Recent average low: 40.2 F (1.4 F above century average)
- Recent average high: 61.1 F (1.3 F above century average)
- #28 warmest year since 1895
- Recent average low: 40.2 F (1.4 F above century average)
- Recent average high: 61.1 F (1.3 F above century average)
#40. Marshall County
- Average temperature, Dec. 2021-Nov. 2022: 51.2 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 40.6 F (1.3 F above century average)
- Recent average high: 61.7 F (1.5 F above century average)
- #27 warmest year since 1895
- Recent average low: 40.6 F (1.3 F above century average)
- Recent average high: 61.7 F (1.5 F above century average)
#39. Ford County
- Average temperature, Dec. 2021-Nov. 2022: 51.5 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 40.7 F (1.5 F above century average)
- Recent average high: 62.4 F (1.4 F above century average)
- #27 warmest year since 1895
- Recent average low: 40.7 F (1.5 F above century average)
- Recent average high: 62.4 F (1.4 F above century average)
#38. Douglas County
- Average temperature, Dec. 2021-Nov. 2022: 53.1 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #31 warmest year since 1895
- Recent average low: 42.5 F (1.4 F above century average)
- Recent average high: 63.7 F (1.5 F above century average)
- #31 warmest year since 1895
- Recent average low: 42.5 F (1.4 F above century average)
- Recent average high: 63.7 F (1.5 F above century average)
#37. Edgar County
- Average temperature, Dec. 2021-Nov. 2022: 53.3 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #26 warmest year since 1895
- Recent average low: 42.4 F (1.1 F above century average)
- Recent average high: 64.2 F (1.7 F above century average)
- #26 warmest year since 1895
- Recent average low: 42.4 F (1.1 F above century average)
- Recent average high: 64.2 F (1.7 F above century average)
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#36. Marion County
- Average temperature, Dec. 2021-Nov. 2022: 55.5 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 44.6 F (1.1 F above century average)
- Recent average high: 66.3 F (1.6 F above century average)
- #24 warmest year since 1895
- Recent average low: 44.6 F (1.1 F above century average)
- Recent average high: 66.3 F (1.6 F above century average)
#35. Richland County
- Average temperature, Dec. 2021-Nov. 2022: 55.6 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 45.4 F (1.7 F above century average)
- Recent average high: 65.8 F (1 F above century average)
- #27 warmest year since 1895
- Recent average low: 45.4 F (1.7 F above century average)
- Recent average high: 65.8 F (1 F above century average)
#34. Clinton County
- Average temperature, Dec. 2021-Nov. 2022: 56 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 44.9 F (0.8 F above century average)
- Recent average high: 67.1 F (2 F above century average)
- #24 warmest year since 1895
- Recent average low: 44.9 F (0.8 F above century average)
- Recent average high: 67.1 F (2 F above century average)
#33. Washington County
- Average temperature, Dec. 2021-Nov. 2022: 56.2 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 45 F (1 F above century average)
- Recent average high: 67.3 F (1.7 F above century average)
- #24 warmest year since 1895
- Recent average low: 45 F (1 F above century average)
- Recent average high: 67.3 F (1.7 F above century average)
#32. Wabash County
- Average temperature, Dec. 2021-Nov. 2022: 56.3 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 46 F (1.6 F above century average)
- Recent average high: 66.6 F (1.1 F above century average)
- #24 warmest year since 1895
- Recent average low: 46 F (1.6 F above century average)
- Recent average high: 66.6 F (1.1 F above century average)
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#31. Perry County
- Average temperature, Dec. 2021-Nov. 2022: 56.4 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 45.3 F (1.4 F above century average)
- Recent average high: 67.5 F (1.3 F above century average)
- #24 warmest year since 1895
- Recent average low: 45.3 F (1.4 F above century average)
- Recent average high: 67.5 F (1.3 F above century average)
#30. St. Clair County
- Average temperature, Dec. 2021-Nov. 2022: 56.6 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 45.4 F (0.7 F above century average)
- Recent average high: 67.7 F (2 F above century average)
- #27 warmest year since 1895
- Recent average low: 45.4 F (0.7 F above century average)
- Recent average high: 67.7 F (2 F above century average)
#29. Gallatin County
- Average temperature, Dec. 2021-Nov. 2022: 57.5 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 46.7 F (1.3 F above century average)
- Recent average high: 68.3 F (1.5 F above century average)
- #23 warmest year since 1895
- Recent average low: 46.7 F (1.3 F above century average)
- Recent average high: 68.3 F (1.5 F above century average)
#28. Pope County
- Average temperature, Dec. 2021-Nov. 2022: 57.6 degrees Fahrenheit (1.4 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 46.8 F (1.3 F above century average)
- Recent average high: 68.5 F (1.5 F above century average)
- #27 warmest year since 1895
- Recent average low: 46.8 F (1.3 F above century average)
- Recent average high: 68.5 F (1.5 F above century average)
#27. McHenry County
- Average temperature, Dec. 2021-Nov. 2022: 48.6 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #27 warmest year since 1895
- Recent average low: 38.4 F (1.1 F above century average)
- Recent average high: 58.9 F (2.1 F above century average)
- #27 warmest year since 1895
- Recent average low: 38.4 F (1.1 F above century average)
- Recent average high: 58.9 F (2.1 F above century average)
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#26. Boone County
- Average temperature, Dec. 2021-Nov. 2022: 48.7 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #29 warmest year since 1895
- Recent average low: 38.6 F (1.2 F above century average)
- Recent average high: 58.9 F (1.8 F above century average)
- #29 warmest year since 1895
- Recent average low: 38.6 F (1.2 F above century average)
- Recent average high: 58.9 F (1.8 F above century average)
#25. Winnebago County
- Average temperature, Dec. 2021-Nov. 2022: 48.9 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #28 warmest year since 1895
- Recent average low: 38.6 F (1.3 F above century average)
- Recent average high: 59.2 F (1.8 F above century average)
- #28 warmest year since 1895
- Recent average low: 38.6 F (1.3 F above century average)
- Recent average high: 59.2 F (1.8 F above century average)
#24. De Witt County
- Average temperature, Dec. 2021-Nov. 2022: 52.4 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 41.6 F (1.1 F above century average)
- Recent average high: 63.1 F (2 F above century average)
- #24 warmest year since 1895
- Recent average low: 41.6 F (1.1 F above century average)
- Recent average high: 63.1 F (2 F above century average)
#23. Piatt County
- Average temperature, Dec. 2021-Nov. 2022: 52.6 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #29 warmest year since 1895
- Recent average low: 41.8 F (1.2 F above century average)
- Recent average high: 63.3 F (1.7 F above century average)
- #29 warmest year since 1895
- Recent average low: 41.8 F (1.2 F above century average)
- Recent average high: 63.3 F (1.7 F above century average)
#22. Coles County
- Average temperature, Dec. 2021-Nov. 2022: 53.7 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #26 warmest year since 1895
- Recent average low: 43.4 F (1.5 F above century average)
- Recent average high: 64 F (1.5 F above century average)
- #26 warmest year since 1895
- Recent average low: 43.4 F (1.5 F above century average)
- Recent average high: 64 F (1.5 F above century average)
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#21. Cumberland County
- Average temperature, Dec. 2021-Nov. 2022: 54.3 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #25 warmest year since 1895
- Recent average low: 44.2 F (1.6 F above century average)
- Recent average high: 64.4 F (1.3 F above century average)
- #25 warmest year since 1895
- Recent average low: 44.2 F (1.6 F above century average)
- Recent average high: 64.4 F (1.3 F above century average)
#20. Jasper County
- Average temperature, Dec. 2021-Nov. 2022: 54.9 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #26 warmest year since 1895
- Recent average low: 45.1 F (2.1 F above century average)
- Recent average high: 64.8 F (0.9 F above century average)
- #26 warmest year since 1895
- Recent average low: 45.1 F (2.1 F above century average)
- Recent average high: 64.8 F (0.9 F above century average)
#19. Clay County
- Average temperature, Dec. 2021-Nov. 2022: 55.5 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 45.1 F (1.8 F above century average)
- Recent average high: 65.8 F (1.3 F above century average)
- #23 warmest year since 1895
- Recent average low: 45.1 F (1.8 F above century average)
- Recent average high: 65.8 F (1.3 F above century average)
#18. Edwards County
- Average temperature, Dec. 2021-Nov. 2022: 56.4 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 46.1 F (1.9 F above century average)
- Recent average high: 66.7 F (1.2 F above century average)
- #23 warmest year since 1895
- Recent average low: 46.1 F (1.9 F above century average)
- Recent average high: 66.7 F (1.2 F above century average)
#17. Hardin County
- Average temperature, Dec. 2021-Nov. 2022: 57.8 degrees Fahrenheit (1.5 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 46.9 F (1.3 F above century average)
- Recent average high: 68.6 F (1.6 F above century average)
- #23 warmest year since 1895
- Recent average low: 46.9 F (1.3 F above century average)
- Recent average high: 68.6 F (1.6 F above century average)
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#16. Wayne County
- Average temperature, Dec. 2021-Nov. 2022: 56.2 degrees Fahrenheit (1.6 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 45.6 F (1.8 F above century average)
- Recent average high: 66.8 F (1.4 F above century average)
- #24 warmest year since 1895
- Recent average low: 45.6 F (1.8 F above century average)
- Recent average high: 66.8 F (1.4 F above century average)
#15. Hamilton County
- Average temperature, Dec. 2021-Nov. 2022: 56.8 degrees Fahrenheit (1.6 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 45.9 F (1.4 F above century average)
- Recent average high: 67.7 F (1.7 F above century average)
- #23 warmest year since 1895
- Recent average low: 45.9 F (1.4 F above century average)
- Recent average high: 67.7 F (1.7 F above century average)
#14. Alexander County
- Average temperature, Dec. 2021-Nov. 2022: 58.4 degrees Fahrenheit (1.6 F above 1901-2000 average)
- #18 warmest year since 1895
- Recent average low: 47.3 F (1.3 F above century average)
- Recent average high: 69.5 F (2 F above century average)
- #18 warmest year since 1895
- Recent average low: 47.3 F (1.3 F above century average)
- Recent average high: 69.5 F (2 F above century average)
#13. Pulaski County
- Average temperature, Dec. 2021-Nov. 2022: 58.4 degrees Fahrenheit (1.6 F above 1901-2000 average)
- #19 warmest year since 1895
- Recent average low: 47.4 F (1.3 F above century average)
- Recent average high: 69.4 F (1.9 F above century average)
- #19 warmest year since 1895
- Recent average low: 47.4 F (1.3 F above century average)
- Recent average high: 69.4 F (1.9 F above century average)
#12. Peoria County
- Average temperature, Dec. 2021-Nov. 2022: 52.1 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #25 warmest year since 1895
- Recent average low: 41.4 F (1.4 F above century average)
- Recent average high: 62.8 F (2 F above century average)
- #25 warmest year since 1895
- Recent average low: 41.4 F (1.4 F above century average)
- Recent average high: 62.8 F (2 F above century average)
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#11. Tazewell County
- Average temperature, Dec. 2021-Nov. 2022: 52.5 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #25 warmest year since 1895
- Recent average low: 41.8 F (1.3 F above century average)
- Recent average high: 63.3 F (2.1 F above century average)
- #25 warmest year since 1895
- Recent average low: 41.8 F (1.3 F above century average)
- Recent average high: 63.3 F (2.1 F above century average)
#10. Clark County
- Average temperature, Dec. 2021-Nov. 2022: 54.4 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #20 warmest year since 1895
- Recent average low: 43.9 F (1.6 F above century average)
- Recent average high: 65 F (1.8 F above century average)
- #20 warmest year since 1895
- Recent average low: 43.9 F (1.6 F above century average)
- Recent average high: 65 F (1.8 F above century average)
#9. Monroe County
- Average temperature, Dec. 2021-Nov. 2022: 57.2 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #15 warmest year since 1895
- Recent average low: 46 F (1.2 F above century average)
- Recent average high: 68.4 F (2.3 F above century average)
- #15 warmest year since 1895
- Recent average low: 46 F (1.2 F above century average)
- Recent average high: 68.4 F (2.3 F above century average)
#8. White County
- Average temperature, Dec. 2021-Nov. 2022: 57.3 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #16 warmest year since 1895
- Recent average low: 46.5 F (1.6 F above century average)
- Recent average high: 67.9 F (1.6 F above century average)
- #16 warmest year since 1895
- Recent average low: 46.5 F (1.6 F above century average)
- Recent average high: 67.9 F (1.6 F above century average)
#7. Massac County
- Average temperature, Dec. 2021-Nov. 2022: 58.5 degrees Fahrenheit (1.7 F above 1901-2000 average)
- #18 warmest year since 1895
- Recent average low: 47.4 F (1.3 F above century average)
- Recent average high: 69.6 F (2 F above century average)
- #18 warmest year since 1895
- Recent average low: 47.4 F (1.3 F above century average)
- Recent average high: 69.6 F (2 F above century average)
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#6. Lake County
- Average temperature, Dec. 2021-Nov. 2022: 49.4 degrees Fahrenheit (1.8 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 40 F (1.6 F above century average)
- Recent average high: 58.9 F (2.1 F above century average)
- #23 warmest year since 1895
- Recent average low: 40 F (1.6 F above century average)
- Recent average high: 58.9 F (2.1 F above century average)
#5. Livingston County
- Average temperature, Dec. 2021-Nov. 2022: 51.4 degrees Fahrenheit (1.8 F above 1901-2000 average)
- #24 warmest year since 1895
- Recent average low: 40.9 F (2 F above century average)
- Recent average high: 62 F (1.6 F above century average)
- #24 warmest year since 1895
- Recent average low: 40.9 F (2 F above century average)
- Recent average high: 62 F (1.6 F above century average)
#4. DuPage County
- Average temperature, Dec. 2021-Nov. 2022: 50.4 degrees Fahrenheit (1.9 F above 1901-2000 average)
- #21 warmest year since 1895
- Recent average low: 40.5 F (1.5 F above century average)
- Recent average high: 60.2 F (2.2 F above century average)
- #21 warmest year since 1895
- Recent average low: 40.5 F (1.5 F above century average)
- Recent average high: 60.2 F (2.2 F above century average)
#3. Woodford County
- Average temperature, Dec. 2021-Nov. 2022: 51.7 degrees Fahrenheit (2 F above 1901-2000 average)
- #23 warmest year since 1895
- Recent average low: 41.1 F (1.9 F above century average)
- Recent average high: 62.4 F (2 F above century average)
- #23 warmest year since 1895
- Recent average low: 41.1 F (1.9 F above century average)
- Recent average high: 62.4 F (2 F above century average)
#2. McLean County
- Average temperature, Dec. 2021-Nov. 2022: 52 degrees Fahrenheit (2 F above 1901-2000 average)
- #20 warmest year since 1895
- Recent average low: 41.3 F (1.9 F above century average)
- Recent average high: 62.8 F (2.2 F above century average)
- #20 warmest year since 1895
- Recent average low: 41.3 F (1.9 F above century average)
- Recent average high: 62.8 F (2.2 F above century average)
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#1. Cook County
- Average temperature, Dec. 2021-Nov. 2022: 51.1 degrees Fahrenheit (2.2 F above 1901-2000 average)
- #16 warmest year since 1895
- Recent average low: 41.6 F (2 F above century average)
- Recent average high: 60.6 F (2.4 F above century average)
- #16 warmest year since 1895
- Recent average low: 41.6 F (2 F above century average)
- Recent average high: 60.6 F (2.4 F above century average)
