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2021 Chicago Marathon Weather Preview

Race, Weather

Race Forecast

October 10, 2021 - Chicago, IL, USA

Overview

The Chicago Marathon is one of the lucky races that is being held on its typical annual date in a year where most marathons have been disrupted due to COVID-19. On the flip side, it has to compete with all the other major marathons that have been pushed to a Fall date, including the Boston Marathon taking place less than 24 hours later. Proof of vaccination status or a negative test must be produced to run. Full COVID-19 protocols for the Chicago Marathon can be found here.

Race Forecast

The Chicago Marathon has had a string of great weather the past few years and it was only matter of time before conditions were not quite as ideal. This year is forecasted to be the hottest since 2007, a year when the race was stopped mid-run for many runners after water had run out. There's a small chance of rain which could bring some relief, but it's not something to rely on. High humidity and a relatively high dew point will mean less sweat evaporating to cool you down and potential overheating.

Chicago Historical Weather

YearRunScoreTempHeat IndexHumidityDew PointRainWind (mph)Cloud CoverUV IndexWBGT
2019
8
43º41º63%31.52º04 5746%151º
2018
9
57º57º97%56.65º0.00684 93100%161º
2017
9
61º61º82%55.25º05 22610%162º
2016
9
54º54º73%45.63º07 12515%154º
2015
9
58º58º68%47.28º05 21313%157º
2014
9
51º51º65%40.2º06 11313%153º
2013
9
55º55º62%41.72º05 3160%154º
2012
8
43º39º58%29.67º07 30370%150º
2011
8
64º64º63%51.33º02 1820%163º
2010
8
69º69º55%51.73º03 26919%166º
2009
7
35º31º62%22.71º04 31173%148º
2008
9
67º67º66%55.22º04 16743%166º
2007
7
76º77º73%66.97º03 20836%176º
2006
6
39º32º81%34.12º011 308100%148º
2005
9
53º53º71%43.68º07 7199%153º
2004
9
54º54º71%45.16º06 12918%154º
2003
9
53º53º75%45.1º09 2700%152º
2002
6
41º33º65%30.02º014 30118%149º
2001
7
40º40º62%28.16º01 29063%150º
2000
8
59º59º72%49.84º013 1301%157º
Historical data collected from Grant Park at 10:00AM. (41.8741868,-87.6295496).
Source historical weather data Powered by Dark Sky. RunScore and WBGT estimates provided by Evening Run.
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