Best Time to See Monarch Butterflies in Colorado
August, September and July is the best time to see monarch butterflies in Colorado. Based on 2,402 verified iNaturalist observations, here is exactly when monarch butterflies 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 June 28, 2026.
2,402 verified observations of monarch butterflies in Colorado, recorded across 9 months of the year on iNaturalist.
When monarch butterflies are recorded in Colorado
Peak month
August
710 records (29.6% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 2 | 0.1% |
| March | 0 | 0% |
| April | 3 | 0.1% |
| May | 16 | 0.7% |
| June | 163 | 6.8% |
| Julypeak | 566 | 23.6% |
| Augustpeak | 710 | 29.6% |
| Septemberpeak | 590 | 24.6% |
| October | 328 | 13.7% |
| November | 24 | 1% |
| December | 0 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 2,402 |
Weather to expect, source Open-Meteo
Typical weather in Colorado
Recent typical conditions by month, so you can plan a trip around both when monarch butterflies are active and what the weather is doing. The best months to look for monarch butterflies sit around 41 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" |
| Jun | 69°F | 42°F | 2.1" |
| Julbest time | 76°F | 49°F | 2.5" |
| Augbest time | 75°F | 48°F | 1.7" |
| Sepbest time | 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.
More on monarch butterflies in Colorado:
Sightings of monarch butterflies in Colorado peak in August, when 710 of the year's 2,402 verified observations are logged — about 29.6% of the annual total. Activity stays high through August, September and July.
The quietest stretch is January, March and December, when monarch butterflies 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 monarch butterflies you are most likely to encounter in Colorado are Monarch — 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 monarch butterflies 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 monarch butterflies in Colorado?+
August is the single best month, and the broader peak window runs through August, September and July, based on 2,402 verified iNaturalist observations.
When are monarch butterflies hardest to see in Colorado?+
January is the quietest month for monarch butterflies in Colorado, with no verified records on iNaturalist.
Are monarch butterflies active year-round in Colorado?+
Monarch butterflies are recorded in 9 of 12 months in Colorado, concentrated around August and September.
More places to see monarch butterflies
More wildlife in Colorado