September Climate Summary for Central and Southeast Illinois

September Rainfall Highlights:

• September was another dry month for the area.  The only rainfall of significance fell on the 18th, where a few locations near the I-74, and I-70 corridors saw in excess of one inch.  Most of the area saw a total of less than one inch of rain in September, while several locations reported less than 0.25".  Springfield saw only 0.01" of rain, ranking as their second driest month since records began in 1879.  Peoria's 0.54" total ranks as their 3rd driest September.  This was the 4th consecutive month of below normal rainfall.  Cumulative rainfall deficits during this four month period were 3" to 9", with the most severe deficits near the I-72 corridor. 
  
  Most of central and southeast Illinois is considered abnormally dry, while a corridor from Jacksonville east through Springfield, Decatur, and Paris is in moderate drought on the latest U.S. Drought Monitor.  Moderate drought is characterized by some damage to crops and pasture, heightened fire danger, and streams, reservoirs, and wells running low.

6/1-9/30 Rainfall Deficit	9/26 Drought Monitor

September Rainfall	September Rainfall Departure from Normal

September Temperature Highlights:

• In contrast to August, September saw much above normal temperatures.  The monthly average temperature was 2 to 5 degrees above normal.  After a cool start to the month, which saw a few record lows in the lower 40s, the last half of the month turned exceptionally warm.  A prolonged stretch of late season heat from the 20th-26th saw daily highs in the lower to middle 90s.  Many sites broke multiple daily record highs during this period.  The following table details records and observed temperatures during this stretch.
   

  		9/20	9/21	9/22	9/23	9/24	9/25	9/26
  Charleston 7 pm	Record 2017	93 95	95 96	95 M	93 M	93 96	91 M	92 95
  Danville 5 pm	Record 2017	95 92	97 93	93 93	91 93	92 93	94 92	91 91
  Decatur midnight	Record 2017	96 90	95 93	94 93	92 92	93 90	91 90	96 90
  Effingham 7 am	Record 2017	96 89	96 96	96 97	95 98	95 95	92 97	93 94
  Galesburg 7 am	Record 2017	91 80	90 92	92 91	89 92	90 92	90 90	92 89
  Jacksonville 7 am	Record 2017	96 87	95 96	96 89	94 96	94 94	93 94	97 92
  Lincoln midnight	Record 2017	94 92	94 94	94 94	92 93	93 91	92 92	91 91
  Normal 5 am	Record 2017	95 85	94 93	94 90	92 95	94 93	93 92	93 92
  Olney 7 am	Record 2017	100 86	100 92	96 93	94 93	94 90	92 92	94 92
  Peoria midnight	Record 2017	94 94	93 91	93 94	92 93	91 91	92 92	93 91
  Springfield midnight	Record 2017	96 96	96 95	95 96	93 95	93 94	94 94	92 94
  Urbana midnight	Record 2017	94 95	95 95	95 95	94 94	94 93	96 91	94 93

September Average Temperature	September Temperature Departure from Normal

Climatological Statistics:

The following links are the monthly and seasonal climate summaries for area cities. Only the summaries for Peoria, Springfield, and Lincoln are considered "official", meaning they are the station of record for their respective locations. The other summaries are "supplemental", meaning another location in the area is the official climate station for the city.

• Peoria -- Peoria International Airport
• Springfield -- Abraham Lincoln Capital Airport
• Lincoln -- NWS Office
• Champaign -- University of Illinois-Willard Airport
• Decatur -- Decatur Airport
• Lawrenceville -- Lawrenceville-Vincennes International Airport
• Mattoon -- Coles County Memorial Airport

Climate data for other cities is available at https://www.weather.gov/climate/xmacis.php?wfo=ilx