An overall drier pattern set in for the Chicago area during the month of August with monthly rainfall totals measuring only 2.05 inches, 2.20 inches below average. With that being said, temperatures were fairly seasonable for this time of year, albeit a tad warmer. The average high temperature was 83.0 degrees and the average low was 65.7 degrees, each 0.5 and 0.6 degrees above average respectively. The average temperature for the month, 74.4 degrees, measured 0.6 degrees above average.
Despite the below average rainfall for the month, August started off rather active for the Windy City. A few showers and storms passed through the area on the 1st as temperatures started off warm in the mid 80s before a warmer, more muggy air mass arrived on the 2nd, pushing highs into the low 90s. A few strong storms developed on the 3rd and brought with it gusty winds, including a microburst that produced 60 - 70 mph wind gusts.
Severe weather reports from August 3rd. Courtesy NWS Chicago.
Additional storms returned on the 4th along with a return to more seasonable temperatures, but only for a brief time. The hottest day of the month was recorded on the 6th, with Chicago O’Hare reaching 95 degrees. The first week of the month closed out with widespread showers and storms the 7th and 8th that produced localized flooding. Western areas saw the highest totals, with Rockford topping 6 inches of rain whereas Chicago itself remained mostly dry, measuring only 0.20 inches at O’Hare.
Rainfall amounts from August 6th into the 8th. Courtesy NWS Chicago.
Cooler temperatures began to set into the region during the second week of the month, with highs reaching only the mid 70s to low 80s. A drier set up came into place as well during this time, with only a few showers and storms returning the 13th and 14th. Tranquil weather returned for the third week, though temperatures began to return to more seasonable levels in the low to mid 80s. A series of scattered storms passed through the Chicago area on the 20th and 21st, producing a total of 0.61 inches at O’Hare (the highest single-day rain total the airport saw in the month).
Chicago closed out with a few heavy rain events. On the 28th, strong thunderstorms passed through northern portions of Illinois and produced scattered wind damage; the most focused damage occurring in DeKalb county. More storms returned the next day and produced heavy rains (with totals upward of 2 inches northwest of Chicago) and damaging wind gusts around 60 mph across the northern Chicago metropolitan area. The month ended dry with temperatures near average.
August was a wetter than average month for the Indianapolis area with temperatures remaining rather seasonable for this time of year. The average high temperature was 84.5 degrees (0.2 above normal) and an average low of 65.5 degrees (0.5 above normal). Overall, the average temperature for August was 75.0 degrees, only 0.3 degrees above normal. Although the month was rather quiet in terms of overall activity, a few heavy rain events helped make August wetter than normal for Indianapolis, with 4.44 inches being recorded (1.24 inches above normal).
The month started off active with a line of severe storms passing through Central Indiana on the 1st. A warmer period held for the first week with temperatures ranging from the high 80s to the low 90s. A high of 93 on the 3rd was the hottest day of the month for Indianapolis. Heat indices during this time pushed into the low 100s and despite a few rounds of storms passing through both the 3rd and 4th, a break from the heat didn’t arrive until the 9th when highs only reached the upper 70s. A moderate rainfall event on the 9th brought with it one of wettest days of the month, with Indianapolis recording 1.21 inches of rain.
The middle third of the month was relatively seasonable and other than a few isolated rain events, remained fairly dry. This quieter period continued into the final week of August before the heat and heavy rainstorms returned. Highs reached above 90 for the first time in nearly three weeks starting on the 28th as some storms passed through that night. A more potent line of storms rolled through on the 29th, bringing with it over 2 inches of rain in some locations. Indianapolis recorded its wettest day of the month with 1.99 inches. Quieter weather returned for the very end of August with temperatures returning to near seasonable levels.
Rainfall amounts on August 30th. Courtesy NWS Indianapolis
Temperatures in August were near normal for this time of year, though the month’s average is a little misleading given the variability of temperatures. Hotter temperatures during the first week of the month were followed by periods of below average highs (with several days not warming out of the 70s). A second warmer period returned at the end of the month, counteracting the cooler period to keep August temperatures around normal. Precipitation varied greatly during August, with portions of the state trending drier than normal (Columbus and Dayton recorded 3.22 and 1.59 inches of rain, 0.52 and 1.37 inches below normal respectively), whereas Cincinnati recorded 7.91 inches of rain this month, nearly 4.5 inches above normal.
The month started off warm and active as storms passed through the region on the 1st, bringing with it gusty winds. A warmer pattern held in place with highs reaching the low 90s. August 3rd was the warmest day of the month for all three cities with highs of 92 in Columbus and Cincinnati and 93 in Dayton. Coupled with elevated humidity levels, heat indices topped 100 degrees throughout the region. A series of repetitive storms affected the southern portion of the state on both the 5th and 6th, producing high rainfall totals and localized flooding. Cincinnati recorded 4.74 inches of rain during this two-day span, over an inch more than the entire monthly average. Although it was not impacted as severely, Columbus also saw its highest rainfall day for the month with this event, measuring 0.72 inches on the 5th.
A few scattered rain events continued through the first half of the month though some areas saw stretches of pleasant, dry conditions. Temperatures cooled to below average as highs ranged from the upper 70s to the low 80s. The 14th saw Columbus tie the day’s record for the coolest high temperature, reaching only 70 degrees.
The second half of the month saw longer stretches of drier conditions, with only a few scattered storm events occurring on the 20th and 21st . Temperatures eventually began to warm as the month came to an end as highs returned to the upper 80s to low 90s. At its hottest, heat indices neared 100 degrees. Aside from a minor disturbance on the 29th and 30th that brought some needed rainfall to otherwise drier areas, the month ended pleasant and seasonable.