The best times to visit Illinois for ideal weather are

April 30th to October 21st

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.



Other Illinois Travel Info

Weather in Illinois


Average temperatures in Illinois vary drastically. Considering humidity, temperatures feel cold for about half of the year and otherwise nice with a low chance of precipitation most of the year. The area is somewhat temperate — in the 44th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Illinois, the hottest months are July, August, and then June. See average monthly temperatures below. The warmest time of year is generally mid July where highs are regularly around 86.9°F (30.5°C) with temperatures rarely dropping below 66.5°F (19.2°C) at night.

Illinois Temperatures (Fahrenheit)


Illinois Temperatures (Celsius)


“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Illinois Perceived Temperature (F)


Illinois Perceived Temperature (C)



Average Illinois Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 35.4 26.3 18.5
Feb 36.5 27.4 19.7
Mar 53.1 42.1 33.4
Apr 65 53 42.8
May 75.7 64 53.6
Jun 83.6 72.6 62.8
Jul 85.8 75.1 65.2
Aug 85 73.8 63.7
Sep 79 66.6 56.2
Oct 67 55 44.9
Nov 53.3 42.8 33.9
Dec 40.7 32.7 25.7

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan 1.9 -3.2 -7.5
Feb 2.5 -2.6 -6.8
Mar 11.7 5.6 0.8
Apr 18.3 11.7 6
May 24.3 17.8 12
Jun 28.7 22.6 17.1
Jul 29.9 23.9 18.4
Aug 29.4 23.2 17.6
Sep 26.1 19.2 13.4
Oct 19.4 12.8 7.2
Nov 11.8 6 1.1
Dec 4.8 0.4 -3.5



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Illinois are January, February, and then November. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around mid January. For example, on the week of January 15th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in late April with an average of 2 days of significant precipitation the week of April 23rd.

When can you find snow in Illinois? Weather stations report large amounts of snow likely to be deepest around February, especially close to early February. The best time to ski (if at all) in Illinois is often around around March 26th when fresh powder is deepest. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.

Chance of Precipitation

The graph below shows the % chance of rainy and snowy days in Illinois.

Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in Illinois (in).

Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 7% 3.6 1.1
Feb 10% 5.8 1.1
Mar 11% 3.2 1.4
Apr 17% 1.5 2.7
May 17% 0 2.6
Jun 19% 0 3.3
Jul 11% 0 2.1
Aug 11% 0 1.9
Sep 11% 0 1.9
Oct 11% 0 1.8
Nov 10% 2.6 1.5
Dec 13% 2.9 2

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 7 9.1 2.8
Feb 10 14.7 2.8
Mar 11 8.1 3.6
Apr 17 3.8 6.9
May 17 0 6.6
Jun 19 0 8.4
Jul 11 0 5.3
Aug 11 0 4.8
Sep 11 0 4.8
Oct 11 0 4.6
Nov 10 6.6 3.8
Dec 13 7.4 5.1


Humidity and Wind

Illinois has some very humid months, with other comfortably humid months. The least humid month is April (53.5% relative humidity), and the most humid month is December (72%).

Wind in Illinois is usually moderate. The windiest month is April, followed by January and February. April’s average wind speed of around 8.8 knots (10.1 MPH or 16.3 KPH) is considered “a gentle breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in early April where average top sustained speeds reach 17.3 knots, which is considered a fresh breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Illinois.

Avg. Relative Humidity


The graph below shows wind speed (max and average) in knots.

Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 8.5 Gentle breeze 15.6 Significant breeze
Feb 8.4 Gentle breeze 15.6 Significant breeze
Mar 8.3 Gentle breeze 15.6 Significant breeze
Apr 8.8 Gentle breeze 17 Strong breeze
May 7.3 Gentle breeze 15.1 Significant breeze
Jun 6.2 Light breeze 14 Significant breeze
Jul 4.9 Light breeze 11.6 Significant breeze
Aug 4.5 Light breeze 10.9 Gentle breeze
Sep 5.2 Light breeze 11.7 Significant breeze
Oct 6.8 Light breeze 13.8 Significant breeze
Nov 7.9 Gentle breeze 14.9 Significant breeze
Dec 8 Gentle breeze 14.8 Significant breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 65.1%
Feb 63.7%
Mar 59.2%
Apr 53.5%
May 57%
Jun 61.6%
Jul 63.8%
Aug 64.7%
Sep 62.1%
Oct 58.6%
Nov 60.8%
Dec 72%


Is it Safe to Travel to Illinois?

Our best data indicates this area is generally safe. As of Dec 04, 2023 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Dec 04, 2023.


The Busiest and Least Crowded Months

The busiest month for tourism in Illinois, United States is June, followed by July and August. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Illinois in December. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month


Most Popular Months to Visit

Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is very reliable. Displayed data is calculated relative to the peak, so a score of 45.7 in December means 45.7% of the tourists vs. June.



Overall Illinois Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderately cold. Highs range from 80.6°F (27°C) and 40°F (4.4°C) with far warmer temperatures in the later months. Rain is somewhat common with 3 to 5 days of significant precipitation per month. Spring is the second busiest for tourism, which makes it a good time for those looking for things to do.

Summer (June through August)

The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see moderate precipitation with 3 to 6 days of precipitation per month. June – August is the busiest season for tourism in Illinois, so lodging and other accommodations may cost more than usual.

Fall (September through November)

Fall daily highs range from 81.9°F (27.7°C) and 46.1°F (7.8°C), which will feel chilly given the humidity and wind. It rains or snows a normal amount: approximately 3 days per month. Tourism is fairly slow during these months due to the weather, so hotels may be lower priced.

Winter (December through February)

Weather is far too cold this time of year in Illinois to be enjoyable for warm weather travelers. The average high during this season is between 41.1°F (5.1°C) and 34°F (1.1°C). On average, it rains or snows a smalll amount: 2 to 4 times per month. These times of year are the slowest with tourists.


Best Times to Travelthe United States › Illinois, United States