Known as the 'Windy City', Chicago experiences warm, humid summers and cold winters.
Chicago weather averages and climate
When is the best time to visit Chicago?
Spring brings a big change in Chicago's weather over a relatively short space of time. Daily highs of 6 Celsius in March are likely with the chance of snow and ice at first. Fast forward to May and highs average around 18. Chicago is not a wet city on average, however around 12 days per month are classed as rainy days, making spring the wettest time of year. Spring is a relatively short season in Chicago but there are certainly many reasons to visit. March sees the famous St. Patrick's Day celebrations which include a huge parade through the downtown area and dying the Chicago River green! Spring sees more than 500 parks across Chicago come into bloom, Lincoln Park is the third most visited park in the USA after New York's Central Park and the National Mall in Washington DC. Late spring is a great time to visit some of Chicago's sights, museums, galleries and parks before the heat of the summer.
Summer in Chicago is typically warm and humid with average highs reaching 27 Celsius in July, the warmest month. Temperatures can vary greatly across the city area due to the effect of Lake Michigan. Lakeside areas can experience an onshore breeze in the summer which makes these areas several degrees cooler than neighbouring areas. The lake breeze may be where Chicago got it's famous nick-name the "Windy City". Chicago can also experience heavy thunderstorms, and summer is by no means dry but with 10 hours of sunshine per day it may be a good time to visit, and perhaps even enjoy one of Chicago's 31 sandy beaches!
September may be the perfect time to visit Chicago as it remains warm and relatively dry with daily highs averaging 23 Celsius. The city hosts a free jazz festival which attracts up to 150,000 visitors. October remains reasonably warm and dry; the Chicago marathon is held around this time. November turns chilly once more with daily highs averaging 8 Celsius, and overnight frosts become more likely.
The winter in Chicago can be severe, with temperatures remaining below freezing for months at a time. Snow and even blizzards are possible, especially in a cold northeasterly with a phenomenon known as "lake effect snow". The city area can benefit from the warmth of the lake during the winter and is often a few degrees warmer than the surrounding area, taking the edge off the biting cold. January is on average the coldest month where temperatures are likely to remain below freezing and any precipitation is almost exclusively snow. Extreme cold can sometimes occur sending temperatures plummeting to as low as minus 30 Celsius! Winter visitors may wish to bring a warm coat!