Monarch Butterflies in Maine in September
Yes, September is one of the best months to see monarch butterflies in Maine. It is the 3rd busiest month of the year, with 1,020 of the 4,130 sightings logged across the year (24.7%), based on verified iNaturalist records.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated June 28, 2026.
Peak month for monarch butterflies in Maine
24.7%
of yearly sightings
1,020
records in September
#3
busiest month of 12
4,130
verified records a year
August 39.1%, September 24.7%, October 6.5%. Busiest month is August at 39.1%.
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 |
In Maine, September carries 24.7% of the year's monarch butterflies sightings, about 16.4 points above an even month-to-month split. That makes it the 3rd busiest of the twelve months, out of 9 months with recorded activity.
Activity is easing off from August (39.1%) into September, and it heads toward October (6.5%) after. This is right inside the peak window, so September is one of the surest months to plan a trip around.
The monarch butterflies most often recorded in Maine are Monarch. Those counts are annual totals rather than a September split, so treat them as which species you are likely to encounter, while the month figures above show how many sightings fall in September itself.
Which monarch butterflies you are most likely to see
- Monarch4,130 records
Plan your monarch butterfly trip in Maine
Start with live tours near Acadia National Park, then compare a nearby stay and a broader wildlife backup before you lock in the trip.
GetYourGuide
Live tours nearbySee live tours near Acadia National Park
Use the live GetYourGuide widget to compare local departures and activity styles close to the main monarch butterfly viewing area.
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Stay nearbyStay near Acadia National Park
Compare hotels, cabins and lodges close to the best monarch butterfly viewing area in Maine.
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Broader backupBook a monarch butterfly tour in Maine
Compare guided wildlife tours, boat trips and nature experiences if you want a second travel network beyond the live widget.
Frequently asked questions
Can you see monarch butterflies in Maine in September?+
Yes. September accounts for 1,020 of the 4,130 verified monarch butterflies sightings logged in Maine across the year, which is 24.7% of the annual total.
Is September a good time to see monarch butterflies in Maine?+
September is one of the best months. It ranks 3rd of the year and sits inside the peak window of August, July and September.
What month is best for monarch butterflies in Maine?+
August is the single busiest month, with the broader peak running through August, July and September, based on 4,130 verified observations.
Which monarch butterflies are you most likely to see in Maine?+
The most-recorded species in Maine are Monarch, based on all-time iNaturalist counts.
See monarch butterflies in Maine in other months
More wildlife in Maine