The best times to visit DeKalb for ideal weather are

May 7th to September 30th

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



Other DeKalb Travel Info

Weather in DeKalb


Average temperatures in DeKalb 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 less temperate than some — in the 39th 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 DeKalb, 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 83.5°F (28.6°C) with temperatures rarely dropping below 63.9°F (17.7°C) at night.

DeKalb Temperatures (Fahrenheit)


DeKalb 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.

DeKalb Perceived Temperature (F)


DeKalb Perceived Temperature (C)



Average DeKalb 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 29.3 21.2 13.9
Feb 29.7 21.8 14.7
Mar 46.8 36.7 29.1
Apr 60.1 47.9 38.1
May 72.8 60.3 49.5
Jun 79.9 69 59.1
Jul 82.1 71.9 62.1
Aug 81 70.4 60.9
Sep 75.4 63.4 53.3
Oct 62.8 51.8 42.4
Nov 48.3 38.9 30.7
Dec 34.8 27.6 20.9

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan -1.5 -6 -10.1
Feb -1.3 -5.7 -9.6
Mar 8.2 2.6 -1.6
Apr 15.6 8.8 3.4
May 22.7 15.7 9.7
Jun 26.6 20.6 15.1
Jul 27.8 22.2 16.7
Aug 27.2 21.3 16.1
Sep 24.1 17.4 11.8
Oct 17.1 11 5.8
Nov 9.1 3.8 -0.7
Dec 1.6 -2.4 -6.2



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in DeKalb are January, February, and then September. 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 DeKalb? Weather stations report no annual snow. 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 DeKalb.

Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in DeKalb (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% 0 0.9
Feb 9% 0 0.9
Mar 12% 0 1.4
Apr 18% 0 2.8
May 19% 0 2.3
Jun 22% 0 2.9
Jul 13% 0 1.5
Aug 16% 0 2.4
Sep 10% 0 1.2
Oct 17% 0 1.8
Nov 11% 0 1.5
Dec 14% 0 1.9

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 7 0 2.3
Feb 9 0 2.3
Mar 12 0 3.6
Apr 18 0 7.1
May 19 0 5.8
Jun 22 0 7.4
Jul 13 0 3.8
Aug 16 0 6.1
Sep 10 0 3
Oct 17 0 4.6
Nov 11 0 3.8
Dec 14 0 4.8


Humidity and Wind

DeKalb has some very humid months, with other comfortably humid months. The least humid month is April (54.9% relative humidity), and the most humid month is December (77.2%).

Wind in DeKalb is usually moderate. The windiest month is April, followed by January and February. April’s average wind speed of around 10.5 knots (12.1 MPH or 19.5 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 to mid April where average top sustained speeds reach 19.4 knots, which is considered a fresh breeze.

Relative Humidity (%)

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

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 10.1 Gentle breeze 17 Strong breeze
Feb 9.8 Gentle breeze 16.8 Significant breeze
Mar 9.5 Gentle breeze 16.6 Strong breeze
Apr 10.5 Gentle breeze 19 Strong breeze
May 9.3 Gentle breeze 17.5 Strong breeze
Jun 7.8 Gentle breeze 15.7 Significant breeze
Jul 6.2 Light breeze 13.1 Strong breeze
Aug 5.7 Light breeze 12.3 Significant breeze
Sep 6.4 Light breeze 12.9 Strong breeze
Oct 8.1 Gentle breeze 15.3 Significant breeze
Nov 9.4 Gentle breeze 16.6 Strong breeze
Dec 9.1 Gentle breeze 16 Significant breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 70.1%
Feb 68%
Mar 63%
Apr 54.9%
May 55.8%
Jun 63.9%
Jul 66.9%
Aug 69.3%
Sep 64.6%
Oct 61.7%
Nov 66.4%
Dec 77.2%


Is it Safe to Travel to DeKalb?

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 DeKalb, IL, US is July, followed by June 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 DeKalb in November. 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 somewhat extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 38.7 in November means 38.7% of the tourists vs. July.



Overall DeKalb Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderately cold. Highs range from 77.3°F (25.2°C) and 32.5°F (0.3°C) with far warmer temperatures in the later months. Rain is somewhat common with 4 to 6 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 comfortable. These months see the most precipitation with 4 to 6 days of precipitation per month. June – August is the busiest season for tourism in DeKalb, so lodging and other accommodations may cost more than usual.

Fall (September through November)

Fall daily highs range from 78.2°F (25.7°C) and 40.7°F (4.8°C), which will feel chilly given the humidity and wind. It rains or snows a normal amount: 3 to 5 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.

Winter (December through February)

Weather is far too cold this time of year in DeKalb to be enjoyable for warm weather travelers. The average high during this season is between 35.4°F (1.9°C) and 26.9°F (-2.8°C). On average, it rains or snows a smalll amount: 2 to 4 times per month. These times of year are fairly slow with tourists.


Best Times to Travelthe United States › DeKalb, IL, US