Best Time to See Squirrels in Illinois
April, May and September is the best time to see squirrels in Illinois. Based on 24,549 verified iNaturalist observations, here is exactly when squirrels are most active across the year in Illinois.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated June 28, 2026.
Eastern Gray Squirrel · toad-wife CC BY
Eastern Chipmunk · Public domain CC0
Eastern Gray Squirrel · Summer J. Smentek CC BY
24,549 verified observations of squirrels in Illinois, recorded across 12 months of the year on iNaturalist.
When squirrels are recorded in Illinois
Peak month
April
3,644 records (14.8% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 1,299 | 5.3% |
| February | 1,309 | 5.3% |
| March | 2,290 | 9.3% |
| Aprilpeak | 3,644 | 14.8% |
| Maypeak | 3,136 | 12.8% |
| June | 2,094 | 8.5% |
| July | 1,284 | 5.2% |
| August | 1,534 | 6.2% |
| Septemberpeak | 2,501 | 10.2% |
| October | 2,416 | 9.8% |
| November | 1,750 | 7.1% |
| December | 1,292 | 5.3% |
Squirrels you are most likely to see
| Species | Verified observations |
|---|---|
| Eastern Gray Squirrel | 13,881 |
| Eastern Chipmunk | 4,523 |
| Eastern Fox Squirrel | 3,453 |
| Groundhog | 1,523 |
| Thirteen-lined Ground Squirrel | 510 |
| Southern Flying Squirrel | 177 |
| American Red Squirrel | 81 |
| Franklin's Ground Squirrel | 5 |
Weather to expect, source Open-Meteo
Typical weather in Illinois
Recent typical conditions by month, so you can plan a trip around both when squirrels are active and what the weather is doing. The best months to look for squirrels sit around 43 to 79 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 38°F | 23°F | 3" |
| Feb | 40°F | 22°F | 3.1" |
| Mar | 53°F | 34°F | 4.8" |
| Aprbest time | 63°F | 43°F | 4.1" |
| Maybest time | 73°F | 54°F | 4.6" |
| Jun | 83°F | 64°F | 3.5" |
| Jul | 85°F | 68°F | 4.3" |
| Aug | 83°F | 66°F | 3.9" |
| Sepbest time | 79°F | 61°F | 3" |
| Oct | 65°F | 48°F | 4.9" |
| Nov | 52°F | 35°F | 1.8" |
| Dec | 45°F | 29°F | 2.3" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Illinois. Weather varies year to year, so treat these as a guide.
More on squirrels in Illinois:
Sightings of squirrels in Illinois peak in April, when 3,644 of the year's 24,549 verified observations are logged — about 14.8% of the annual total. Activity stays high through April, May and September.
The quietest stretch is July, December and January, when squirrels are hardest to find — July sees just 1,284 records. If a reliable sighting matters, plan around the peak window rather than the off-season.
The squirrels you are most likely to encounter in Illinois are Eastern Gray Squirrel, Eastern Chipmunk and Eastern Fox Squirrel — the most-recorded species in the state. Each keeps its own seasonal rhythm, but the month-by-month pattern above reflects every reported sighting together.
Where to go
Best places to see squirrels in Illinois
- Lewis & Clark National Historic Trail — National Historic Trail
- Lincoln Home National Historic Site — National Historic Site
- Emmett Till and Mamie Till-Mobley National Monument — National Monument
- Mormon Pioneer National Historic Trail — National Historic Trail
- New Philadelphia National Historic Site — National Historic Site
- Pullman National Historical Park — National Historical Park
Gear to see them
Frequently asked questions
What is the best month to see squirrels in Illinois?+
April is the single best month, and the broader peak window runs through April, May and September, based on 24,549 verified iNaturalist observations.
When are squirrels hardest to see in Illinois?+
July is the quietest month for squirrels in Illinois, with only 1,284 verified records.
Are squirrels active year-round in Illinois?+
Squirrels are recorded in 12 of 12 months in Illinois, so they can be seen year-round, with a clear peak in April.
More places to see squirrels
More wildlife in Illinois