September 2026 Climate Summary

September 2026 Climate Review:

Temperatures averaged well above normal by 7 to 8 degrees. It was the warmest September on record in Cape Girardeau and Poplar Bluff, while the other 3 sites all finished as a top 4 warmest September. We absolutely baked during the first 3 weeks of the month, and we were on pace to break the warmest September on record across the entire region until a much cooler pattern finally set in on the 22nd. High temperatures ranged from the mid 90s to low 100s most days during the first 3 weeks of the month, with Paducah witnessing 13 days with a high temperature of 95 or greater which is a September record (previous most was 12 in 1939). While everywhere hit 100 degrees at least once, Poplar Bluff led the way with 6 days (2nd most in the month of September only behind the 8 days in 1925). Humidity levels were also unusually high by September standards, more on par with what we would expect during peak summertime in July. This lead to numerous days with heat index readings reaching near or above 105 degrees. Our office issued our latest Extreme Heat Warning on record during the September 1-5 heat wave. Somewhat cooler weather followed the week after, besides for a brief spike to Heat Advisory levels on the 9th. Another prolonged heat wave impacted our region from the 15th through 19th leading to a Heat Advisory being issued. This was the latest in the season we had issued a Heat Advisory dating back to 1995 (previous latest was September 5, 2014 and 2012). Paducah set September records for the number of hours with heat index readings reaching both 105 and 100 degrees. We also set September records for the number of hours with a dew point reaching both 75 and 70 degrees. A strong cold front finally cooled us down significantly on the 22nd when highs were only in the upper 60s to mid 70s. While some moderation occurred from the 24th through 28th, high temperatures remained near to slightly below normal in the mid 70s to low 80s. Overnight lows dipped into the 50s most of these nights. The coldest mornings were on the 28th and 29th when many stations dipped into the mid to upper 40s! The final day of the month brought a return of highs in the low to mid 90s.

Precipitation was below normal across our region with many areas observing 1 to 3” deficits for September. Amounts generally ranged from 0.5 to 2.5”. There were some areas that received less than a half inch though, mainly confined to portions of southeast Missouri, Alexander and Pulaski Counties in Illinois, and parts of the Pennyrile region of west Kentucky. Meanwhile some heavier swaths of 2.5 to 3.5” were focused across the Jackson Purchase area of west Kentucky and northeastward into portions of southeast Illinois and southwest Indiana nearest to the Wabash River. Another small area of higher amounts occurred across Ripley County Missouri. The highest observed amount in our forecast area was 3.85” at a CoCoRaHS station in Wabash County Illinois (Mount Carmel 4.2 NW). Abnormally dry conditions increased from 21% coverage across our region at the beginning of September to 87% by the end of the month. Meanwhile the amount of the area in moderate drought increased from 6% to 22%, primarily focused across the Ozark Foothills of southeast Missouri and the southern Pennyrile of west Kentucky.