Monarch Butterflies in Washington in September
Yes, September is one of the best months to see monarch butterflies in Washington. It is the 3rd busiest month of the year, with 28 of the 131 sightings logged across the year (21.4%), 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 Washington
21.4%
of yearly sightings
28
records in September
#3
busiest month of 12
131
verified records a year
August 30.5%, September 21.4%, October 12.2%. Busiest month is August at 30.5%.
131 verified observations of monarch butterflies in Washington, recorded across 8 months of the year on iNaturalist.
When monarch butterflies are recorded in Washington
Peak month
August
40 records (30.5% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 0 | 0% |
| March | 0 | 0% |
| April | 2 | 1.5% |
| May | 1 | 0.8% |
| June | 6 | 4.6% |
| Julypeak | 37 | 28.2% |
| Augustpeak | 40 | 30.5% |
| Septemberpeak | 28 | 21.4% |
| October | 16 | 12.2% |
| November | 1 | 0.8% |
| December | 0 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 131 |
In Washington, September carries 21.4% of the year's monarch butterflies sightings, about 13.1 points above an even month-to-month split. That makes it the 3rd busiest of the twelve months, out of 8 months with recorded activity.
Activity is easing off from August (30.5%) into September, and it heads toward October (12.2%) 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 Washington 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
- Monarch131 records
Plan your monarch butterfly trip in Washington
Start with live tours near Ebey's Landing National Historical Reserve, then compare a nearby stay and a broader wildlife backup before you lock in the trip.
GetYourGuide
Live tours nearbySee live tours near Ebey's Landing National Historical Reserve
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 Ebey's Landing National Historical Reserve
Compare hotels, cabins and lodges close to the best monarch butterfly viewing area in Washington.
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Broader backupBook a monarch butterfly tour in Washington
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 Washington in September?+
Yes. September accounts for 28 of the 131 verified monarch butterflies sightings logged in Washington across the year, which is 21.4% of the annual total.
Is September a good time to see monarch butterflies in Washington?+
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 Washington?+
August is the single busiest month, with the broader peak running through August, July and September, based on 131 verified observations.
Which monarch butterflies are you most likely to see in Washington?+
The most-recorded species in Washington are Monarch, based on all-time iNaturalist counts.
See monarch butterflies in Washington in other months
More wildlife in Washington