Best Time to See Monarch Butterflies in Maine
August, July and September is the best time to see monarch butterflies in Maine. Based on 4,130 verified iNaturalist observations, here is exactly when monarch butterflies are most active across the year in Maine.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated June 28, 2026.
4,130 verified observations of monarch butterflies in Maine, recorded across 9 months of the year on iNaturalist.
When monarch butterflies are recorded in Maine
Peak month
August
1,615 records (39.1% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 0 | 0% |
| March | 0 | 0% |
| April | 2 | 0% |
| May | 15 | 0.4% |
| June | 120 | 2.9% |
| Julypeak | 1,072 | 26% |
| Augustpeak | 1,615 | 39.1% |
| Septemberpeak | 1,020 | 24.7% |
| October | 270 | 6.5% |
| November | 15 | 0.4% |
| December | 1 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 4,130 |
Weather to expect, source Open-Meteo
Typical weather in Maine
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 53 to 80 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 28°F | 11°F | 4" |
| Feb | 28°F | 11°F | 3.1" |
| Mar | 39°F | 20°F | 2.7" |
| Apr | 51°F | 32°F | 4.8" |
| May | 64°F | 43°F | 3.2" |
| Jun | 74°F | 54°F | 3.7" |
| Julbest time | 80°F | 62°F | 4.9" |
| Augbest time | 77°F | 60°F | 4.7" |
| Sepbest time | 69°F | 53°F | 4.4" |
| Oct | 58°F | 43°F | 5.3" |
| Nov | 43°F | 29°F | 3.8" |
| Dec | 34°F | 20°F | 5" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Maine. Weather varies year to year, so treat these as a guide.
More on monarch butterflies in Maine:
Sightings of monarch butterflies in Maine peak in August, when 1,615 of the year's 4,130 verified observations are logged — about 39.1% of the annual total. Activity stays high through August, July and September.
The quietest stretch is January, February and March, 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 Maine 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 Maine
- Acadia National Park — National Park
- Appalachian National Scenic Trail — National Scenic Trail
- Katahdin Woods and Waters National Monument — National Monument
- Saint Croix Island International Historic Site — International Historic Site
- Frances Perkins National Monument — National Monument
- Maine Acadian Culture
Frequently asked questions
What is the best month to see monarch butterflies in Maine?+
August is the single best month, and the broader peak window runs through August, July and September, based on 4,130 verified iNaturalist observations.
When are monarch butterflies hardest to see in Maine?+
January is the quietest month for monarch butterflies in Maine, with no verified records on iNaturalist.
Are monarch butterflies active year-round in Maine?+
Monarch butterflies are recorded in 9 of 12 months in Maine, concentrated around August and July.
More places to see monarch butterflies
More wildlife in Maine