Best Time to See Monarch Butterflies in Massachusetts
August, July and September is the best time to see monarch butterflies in Massachusetts. Based on 8,131 verified iNaturalist observations, here is exactly when monarch butterflies are most active across the year in Massachusetts.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated June 28, 2026.
8,131 verified observations of monarch butterflies in Massachusetts, recorded across 11 months of the year on iNaturalist.
When monarch butterflies are recorded in Massachusetts
Peak month
August
2,622 records (32.2% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 1 | 0% |
| March | 1 | 0% |
| April | 4 | 0% |
| May | 61 | 0.8% |
| June | 500 | 6.1% |
| Julypeak | 2,555 | 31.4% |
| Augustpeak | 2,622 | 32.2% |
| Septemberpeak | 1,762 | 21.7% |
| October | 594 | 7.3% |
| November | 29 | 0.4% |
| December | 2 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 8,131 |
Weather to expect, source Open-Meteo
Typical weather in Massachusetts
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 56 to 83 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 37°F | 22°F | 3.8" |
| Feb | 39°F | 22°F | 3.4" |
| Mar | 48°F | 28°F | 3.6" |
| Apr | 57°F | 38°F | 4.6" |
| May | 68°F | 47°F | 3.4" |
| Jun | 78°F | 58°F | 3.6" |
| Julbest time | 83°F | 65°F | 5.4" |
| Augbest time | 82°F | 64°F | 3.5" |
| Sepbest time | 73°F | 56°F | 5.3" |
| Oct | 62°F | 47°F | 5.3" |
| Nov | 50°F | 34°F | 3.1" |
| Dec | 42°F | 27°F | 5.9" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Massachusetts. Weather varies year to year, so treat these as a guide.
More on monarch butterflies in Massachusetts:
Sightings of monarch butterflies in Massachusetts peak in August, when 2,622 of the year's 8,131 verified observations are logged — about 32.2% 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 Massachusetts 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 Massachusetts
- Appalachian National Scenic Trail — National Scenic Trail
- Blackstone River Valley National Historical Park — National Historical Park
- Boston Harbor Islands National Recreation Area — National Recreation Area
- Cape Cod National Seashore — National Seashore
- Adams National Historical Park — National Historical Park
- Boston African American National Historic Site — National Historic Site
Frequently asked questions
What is the best month to see monarch butterflies in Massachusetts?+
August is the single best month, and the broader peak window runs through August, July and September, based on 8,131 verified iNaturalist observations.
When are monarch butterflies hardest to see in Massachusetts?+
January is the quietest month for monarch butterflies in Massachusetts, with no verified records on iNaturalist.
Are monarch butterflies active year-round in Massachusetts?+
Monarch butterflies are recorded in 11 of 12 months in Massachusetts, so they can be seen year-round, with a clear peak in August.
More places to see monarch butterflies
More wildlife in Massachusetts