Best Time to See Rattlesnakes in Colorado
July, June and August is the best time to see rattlesnakes in Colorado. Based on 3,301 verified iNaturalist observations, here is exactly when rattlesnakes are most active across the year in Colorado.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated July 22, 2026.
Eastern Diamondback Rattlesnake · Scott Allen Davis CC BY
Panamint Rattlesnake · Matt Berger CC BY
Red Diamond Rattlesnake · Amy Huie CC BY
3,301 verified observations of rattlesnakes in Colorado, recorded across 11 months of the year on iNaturalist.
When rattlesnakes are recorded in Colorado
Peak month
July
804 records (24.4% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 1 | 0% |
| March | 16 | 0.5% |
| April | 155 | 4.7% |
| May | 486 | 14.7% |
| Junepeak | 661 | 20% |
| Julypeak | 804 | 24.4% |
| Augustpeak | 507 | 15.4% |
| September | 417 | 12.6% |
| October | 213 | 6.5% |
| November | 40 | 1.2% |
| December | 1 | 0% |
Rattlesnakes you are most likely to see
| Species | Verified observations |
|---|---|
| Prairie Rattlesnake | 3,244 |
| Western Rattlesnake | 54 |
Weather to expect, source Open-Meteo
Typical weather in Colorado
Recent typical conditions by month, so you can plan a trip around both when rattlesnakes are active and what the weather is doing. The best months to look for rattlesnakes sit around 42 to 76 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 27°F | 5°F | 0.5" |
| Feb | 27°F | 3°F | 0.9" |
| Mar | 34°F | 9°F | 1.3" |
| Apr | 46°F | 20°F | 1.1" |
| May | 57°F | 31°F | 2.5" |
| Junbest time | 69°F | 42°F | 2.1" |
| Julbest time | 76°F | 49°F | 2.5" |
| Augbest time | 75°F | 48°F | 1.7" |
| Sep | 69°F | 41°F | 1.1" |
| Oct | 54°F | 27°F | 0.8" |
| Nov | 40°F | 18°F | 0.6" |
| Dec | 30°F | 10°F | 0.9" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Colorado. Weather varies year to year, so treat these as a guide.
Sightings of rattlesnakes in Colorado peak in July, when 804 of the year's 3,301 verified observations are logged — about 24.4% of the annual total. Activity stays high through July, June and August.
The quietest stretch is January, February and December, when rattlesnakes are hardest to find — no verified records exist for January. If a reliable sighting matters, plan around the peak window rather than the off-season.
The rattlesnakes you are most likely to encounter in Colorado are Prairie Rattlesnake and Western Rattlesnake — 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 rattlesnakes in Colorado
- Bent's Old Fort National Historic Site — National Historic Site
- Black Canyon Of The Gunnison National Park — National Park
- Colorado National Monument — National Monument
- Curecanti National Recreation Area — National Recreation Area
- Dinosaur National Monument — National Monument
- Great Sand Dunes National Park & Preserve — National Park & Preserve
Frequently asked questions
What is the best month to see rattlesnakes in Colorado?+
July is the single best month, and the broader peak window runs through July, June and August, based on 3,301 verified iNaturalist observations.
When are rattlesnakes hardest to see in Colorado?+
January is the quietest month for rattlesnakes in Colorado, with no verified records on iNaturalist.
Are rattlesnakes active year-round in Colorado?+
Rattlesnakes are recorded in 11 of 12 months in Colorado, so they can be seen year-round, with a clear peak in July.
More wildlife in Colorado