A Warmer September in the Midwest

October 10, 2023 // Article by: Shawn McGarrity


September saw temperatures and precipitation trend higher than normal, with the average temperature being 69.5°F (3.2°F warmer than normal) and the month’s rainfall measuring 3.36” (normally 3.19”).

The month started off warm with temperatures ranging from the mid 80s to the 90s during the first week. High temperatures from the 3rd to the 5th tied at the month’s warmest; 94°F. Quieter conditions were around too, with the first shot at rainfall arriving on the 5th in the form of showers and storms. Some of the storms produced wind gusts to 60 mph, bringing down some branches and weaker trees, but otherwise severe weather was rather absent in September. Heavier rains developed on the 6th, though the most torrential rainfall developed just south of the Chicagoland area. A few lingering rounds of returning showers and storms persisted through to the 8th.

Rainfall amounts following the September 5th/6th event. Courtesy of NWS Chicago.

Once this period of unsettled weather came to a close, temperatures returned to more seasonable levels as daytime highs settled into the 70s. After a few showers passed through the area on the 10th, a slow-moving front brought a decent rainfall to the region on the 11th with O’Hare measuring 0.77”. Once this system cleared out, the Chicago area saw several days of more settled weather. 

Showers and storms returned to the area on the 16th and 17th, with the latter bringing a good soaking rain across the region and produced the highest rainfall totals for the month. O’Hare measured 1.60”, whereas locations in southern Cook County saw locally over 5” of rain.

Rainfall reports from the September 17th event. Courtesy of NWS Chicago. 

Unsettled weather continued at times into the second half of the month, with scattered showers on around from the 19th through the 22nd. Temperatures saw a bit of a warming trend during this time, with highs reaching into the low 80s from the 20th to the 23rd. 

Another slow-moving system approached the area beginning on the 25th, however activity was more hit-or-miss in nature and provided occasional showers and storms to the region through to the 28th before the low pressure pushed to the east. Temperature settled back into the 70s on the back side of the departing system, with quieter conditions returning to close out the month. 


Similar to other parts of the Midwest, temperatures trended warmer than average in the Indianapolis area with temperatures averaging 69.9°F (2.1°F above normal). Precipitation for the month fell short of normal, however, with only 1.60” of the typical 3.14” falling throughout September. 

The month started off warmer than average with highs in the 80s, peaking at 90°F on both the 4th and 5th (tying for the warmest day of the month). Conditions remained quiet during this time before scattered showers returned on the 5th, bringing with it a break from the late-summer heat as highs returned to the 70s. 

Beyond the initial showers on the 5th (and minimal spotty showers in the subsequent two days), drier conditions returned to the area. This persisted well into the middle of the month, with the only breaks in the otherwise settled pattern coming from a few showers on the 11th/12th and again on the 16th/17th. 

Temperatures felt more like summer heading into the final third of the month as daytime highs warmed back into the 80s starting on the 20th. Showers and storms did not return to the region until 26th when a slow-moving disturbance brought with it several days of unsettled weather. Initially, activity was more of the hit-or-miss variety, however more organized storms and downpours on the 27th allowed for 1.42” of rain to fall (the wettest day of the month and encompassing a vast majority of the month’s total rainfall). 

24hr Rainfall in Central Indiana thru 8 AM, Sept. 28th. Courtesy of NWS Indianapolis.

More seasonable temperatures returned on the back side of this system as September came to a close. Lingering showers exited by the 29th with a drier pattern taking hold that carried on into the start of October. 


A hot start to the month coupled with a returning warm period at the end of the month allowed for overall temperatures to average higher than normal for the region. Columbus and Cincinnati had  average temperatures of 68.9°F and 70°F, which were 1.7°F and 1.9°F warmer than normal, respectively. Precipitation, to the contrary, fell well short of normal for both cities, with Columbus only measuring 0.77” (typically 3.14”) and Cincinnati only 0.94” (typically 3.11”).

A prolonged period of dry weather persisted through the first week of September with the first return of showers developing on the 7th. During this time, temperatures started off warm with highs in the low 90s (peaking at 93°F on the 4th/5th in Columbus, 92°F on the 5th in Cincinnati). Temperatures settled back into the 70s with the arrival of showers on the 7th. 

A frontal system on the 12th brought the first round of more organized showers and storms to the region, which was followed by another stretch of settled weather before showers returned on the 16th for both cities. A few showers lingered in Columbus into the 17th before another week-long duration of quieter conditions returned. 

Highs returned to the low 80s as part of a warmer spell that lasted from the 20th to the 26th. A slow-moving system worked through the Midwest beginning on the 25th, bringing scattered showers and storms to the Ohio region. Cincinnati, while largely missed by more impressive downpours, managed to measure 0.37” of rainfall on the 26th, the wettest day of the month. More organized activity on the 28th brought 0.47” of rain to Columbus, proving to be their wettest day. 

Once the system exited the region on the 29th, quieter weather took hold to close out the month as high temperatures returned back to the 70s.