Monarch Butterflies in Connecticut in September
Yes, September is one of the best months to see monarch butterflies in Connecticut. It is the 3rd busiest month of the year, with 919 of the 3,676 sightings logged across the year (25%), 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 Connecticut
25%
of yearly sightings
919
records in September
#3
busiest month of 12
3,676
verified records a year
August 35.3%, September 25%, October 6.1%. Busiest month is August at 35.3%.
3,676 verified observations of monarch butterflies in Connecticut, recorded across 9 months of the year on iNaturalist.
When monarch butterflies are recorded in Connecticut
Peak month
August
1,298 records (35.3% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 0 | 0% |
| March | 1 | 0% |
| April | 2 | 0.1% |
| May | 42 | 1.1% |
| June | 217 | 5.9% |
| Julypeak | 960 | 26.1% |
| Augustpeak | 1,298 | 35.3% |
| Septemberpeak | 919 | 25% |
| October | 224 | 6.1% |
| November | 13 | 0.4% |
| December | 0 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 3,676 |
In Connecticut, September carries 25% of the year's monarch butterflies sightings, about 16.7 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 (35.3%) into September, and it heads toward October (6.1%) 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 Connecticut 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
- Monarch3,676 records
Plan your monarch butterfly trip in Connecticut
Start with live tours near Appalachian National Scenic Trail, then compare a nearby stay and a broader wildlife backup before you lock in the trip.
GetYourGuide
Live tours nearbySee live tours near Appalachian National Scenic Trail
Use the live GetYourGuide widget to compare local departures and activity styles close to the main monarch butterfly viewing area.
Booking.com
Stay nearbyStay near Appalachian National Scenic Trail
Compare hotels, cabins and lodges close to the best monarch butterfly viewing area in Connecticut.
Viator
Broader backupBook a monarch butterfly tour in Connecticut
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 Connecticut in September?+
Yes. September accounts for 919 of the 3,676 verified monarch butterflies sightings logged in Connecticut across the year, which is 25% of the annual total.
Is September a good time to see monarch butterflies in Connecticut?+
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 Connecticut?+
August is the single busiest month, with the broader peak running through August, July and September, based on 3,676 verified observations.
Which monarch butterflies are you most likely to see in Connecticut?+
The most-recorded species in Connecticut are Monarch, based on all-time iNaturalist counts.
See monarch butterflies in Connecticut in other months
More wildlife in Connecticut