Statewide
Colorado Reptiles and Amphibians by Month
Every reptile and amphibian with enough records anywhere in Colorado, counted from observations inside the state line. Seasons can differ a lot across the state, so for a closer match, pick your ecoregion on the Colorado page.
45 species1 venomous
Peak and shoulder ratings are rough guidance, not a schedule. Weather, elevation and the year can shift any species by weeks.
Rare and protected species are left off on purpose. Look, don't take, and never handle a venomous snake.
Species out in Colorado, by group and month
| Group | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snakes | 5 | 15 | 17 | 17 | 16 | 16 | 14 | 11 | 5 | 1 | ||
| Lizards | 2 | 6 | 12 | 13 | 13 | 13 | 13 | 12 | 7 | 3 | ||
| Turtles | 2 | 3 | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 3 | ||
| Frogs and Toads | 1 | 1 | 3 | 5 | 9 | 9 | 9 | 9 | 8 | 5 | 2 | 1 |
| Salamanders | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Numbers = species active that month (at peak or just starting / winding down).
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40 species at peak or shoulder in September
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shoulderAbout Colorado
When are reptiles and amphibians most active in Colorado?
June is the busiest month in Colorado, with 39 species at peak activity. At least half of the area's species are active from April through October.
What reptiles and amphibians live in Colorado?
45 species have enough iNaturalist records to show here: 17 snakes, 13 lizards, 9 frogs and toads, 5 turtles, and 1 salamander. The most-reported are the Western Terrestrial Garter Snake, Woodhouse's Toad, and Gopher Snake.
Are there venomous snakes in Colorado?
Yes. The Prairie Rattlesnake lives here. Don't handle them.
Which reptiles and amphibians in Colorado are introduced?
The Pond Slider is not native here.
Where does this data come from?
Activity calendars are built from iNaturalist research-grade observations (downloaded through GBIF, September 2026), corrected for how many people are out observing each month. Rare and protected species are left off on purpose.