Chicago Weather in May

May brings plenty of pleasantly warm weather to Chicago, Illinois. This is also the city's least humid month of the year.

This page gives detailed information on the typical May weather for Chicago.

You can jump directly to data and descriptions for:

The numbers here are historical averages based on climate data gathered at the Chicago O'Hare International Airport, located in the northwestern part of Chicago.

Temperature Weather iconTemperature

70 °F May average high 21 °C
48 °F May average low 9 °C

In most years, Chicago averages a daily maximum temperature for May that's between 66 and 74 degrees Fahrenheit (19 to 23 degrees Celsius). The minimum temperature usually falls between 45 and 52 °F (7 to 11 °C).

The days at Chicago warm steadily during May. By the end of the month, the temperature has climbed around 10 °F (5 °C) above what it was at the start.

15 days 70 °F max. or more (21 °C)
19 days 50 °F min. or less (10 °C)

The temperature rises nearly every day in May to over 50 °F (10 °C) in Chicago. The city averages 6 days this month when the thermometer reaches into the 80s °F (over 26 °C). Temperatures above 90 °F (32 °C) occur in May every couple of years.

The thermometer dips to 40 °F (4 °C) or below on 4 nights. But in most years May never gets cold enough for frost.

Rainy Weather iconRain

3.7 in total precipitation 93 mm
12 days of rain

Half the time, Chicago receives 2 to 5 inches (53 to 124 mm) of rainfall in May. One in four years has drier weather, while another one in four is wetter. None of the precipitation falls as snow.

Sunny Weather iconSun

58 % sunshine
7 days clear skies

The sun's rays reach the ground in Chicago during 58 percent of daylight hours on average in May, for a total of 262 hours in the month. Typically on 7 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in May at Chicago lasts for 14 hours and 34 minutes a day on average. The shortest day of the month is the 1st with 14 hours and 3 minutes of daylight. By the end of the month, the days have lengthened to 15:00 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

64 % May average humidity

The relative humidity in Chicago during May usually peaks at 77 percent in the morning then drops to 51 percent by mid afternoon. May is the least humid month for Chicago.

Local Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 73 77 77 61 53 51 54 66

Windy Weather iconWind

10.5 mph May wind speed average 16.9 kph

May is a little windier than most other months in Chicago.

Stormy Weather iconStorms

2 days rainfall of 0.5 inches (13 mm) or more
5 days with thunderstorms in May

May is an average month for storm activity around Chicago.


These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals.

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