Best Time to See Snakes in Illinois
April, May and October is the best time to see snakes in Illinois. Based on 24,551 verified iNaturalist observations, here is exactly when snakes 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 Hognose Snake · psweet CC BY-SA
Northern Cottonmouth · Chris Stahl CC BY
Queensnake · Jared Shorma CC BY
24,551 verified observations of snakes in Illinois, recorded across 12 months of the year on iNaturalist.
When snakes are recorded in Illinois
Peak month
April
5,301 records (21.6% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 29 | 0.1% |
| February | 119 | 0.5% |
| March | 1,811 | 7.4% |
| Aprilpeak | 5,301 | 21.6% |
| Maypeak | 4,759 | 19.4% |
| June | 2,951 | 12% |
| July | 1,544 | 6.3% |
| August | 1,365 | 5.6% |
| September | 2,422 | 9.9% |
| Octoberpeak | 3,870 | 15.8% |
| November | 332 | 1.4% |
| December | 48 | 0.2% |
Snakes you are most likely to see
| Species | Verified observations |
|---|---|
| Common Garter Snake | 4,196 |
| Common Watersnake | 2,997 |
| DeKay's Brownsnake | 2,838 |
| Northern Cottonmouth | 2,710 |
| Plains Garter Snake | 2,272 |
| Central Ratsnake | 1,464 |
| Eastern Foxsnake | 1,029 |
| North American Racer | 855 |
Weather to expect, source Open-Meteo
Typical weather in Illinois
Recent typical conditions by month, so you can plan a trip around both when snakes are active and what the weather is doing. The best months to look for snakes sit around 43 to 73 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" |
| Sep | 79°F | 61°F | 3" |
| Octbest time | 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 snakes in Illinois:
Sightings of snakes in Illinois peak in April, when 5,301 of the year's 24,551 verified observations are logged — about 21.6% of the annual total. Activity stays high through April, May and October.
The quietest stretch is January, when snakes are hardest to find — January sees just 29 records. If a reliable sighting matters, plan around the peak window rather than the off-season.
The snakes you are most likely to encounter in Illinois are Common Garter Snake, Common Watersnake and DeKay's Brownsnake — 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 snakes 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 snakes in Illinois?+
April is the single best month, and the broader peak window runs through April, May and October, based on 24,551 verified iNaturalist observations.
When are snakes hardest to see in Illinois?+
January is the quietest month for snakes in Illinois, with only 29 verified records.
Are snakes active year-round in Illinois?+
Snakes 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 snakes
More wildlife in Illinois