Chicago Marathon 2023: Weather forecast for race day

It’s that time of year again. While the fall marathon season can bring PR-worthy conditions, there’s always the threat of a random cold front moving in or August rearing its head.

But if you’re running the Chicago Marathon on Sunday, you’re in for a treat. The forecast looks almost perfect, with temperatures in the high 40s and low 50s on race morning with some cloud coverage and moderate winds. Humidity is expected to range between 50 to 70 percent, and no rain is expected.

Some of you may be breathing a sigh of relief. The first week of October has been unseasonably warm in the Windy City so far, with daily highs in the low 80s at the start of the week, until dipping into the 60s on Thursday. Fortunately, the weekend returned to cooler weather.

Here’s a quick look at the weather forecast for Sunday, according to Weather Underground.

For a bit of historical context, the 2019 Chicago Marathon — which saw Brigid Kosgei set the (now broken) women’s world record of 2:14:04 — had great weather. Temperatures were in the low to mid 40s in the morning before peaking at 55 degrees at 2 p.m. Last year’s race was a bit warmer, with temperatures reaching the high 40s in the early morning before rising to 71 degrees in the mid-afternoon. According to the National Weather Service, the historically average temperature on October 8 in Chicago was 57 degrees.

Just a few weeks ago at the Berlin Marathon, Tgest Assefa broke Kosgei’s world record by more than two minutes, thanks in part to marathon-friendly weather. Conditions were in the 50s with some cloud coverage.

If you follow current news, you know that bad weather at a marathon can greatly impact the race. The Twin Cities Marathon and 10 Mile in Minnesota last weekend were canceled at the last minute due to warm conditions deemed dangerous for participants. Back in May, the Flying Pig Marathon in Cincinnati, Ohio, faced criticism after runners were told to “shelter in place” during the race after strong thunderstorms.

But so far, it looks like smooth sailing for Sunday in Chicago.

Need some help choosing race day clothes? Verify what to wear a tool. Simply enter the weather condition, and it will give you some suggestions to dress accordingly.

Theo Kahler is news editor at The world of hostility. He is a former all-conference collegiate runner based in Easton, Pennsylvania. He previously worked as a newsletter editor for The world of hostility, CyclingAnd Popular Mechanics.