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In terms of precipitation, rainfall in Chicago O'Hare Intl Airport ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Chicago O'Hare Intl Airport when rainfall is around 1.7 in.
If weather is an important factor for your trip to Chicago O'Hare Intl Airport, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).