Monarch Butterflies in Iowa in September
Yes, September is one of the best months to see monarch butterflies in Iowa. It is the 2nd busiest month of the year, with 702 of the 2,532 sightings logged across the year (27.7%), 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 July 2, 2026.
Peak month for monarch butterflies in Iowa
27.7%
of yearly sightings
702
records in September
#2
busiest month of 12
2,532
verified records a year
August 30.9%, September 27.7%, October 4.9%. Busiest month is August at 30.9%.
2,532 verified observations of monarch butterflies in Iowa, recorded across 9 months of the year on iNaturalist.
When monarch butterflies are recorded in Iowa
Peak month
August
783 records (30.9% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 0 | 0% |
| February | 0 | 0% |
| March | 2 | 0.1% |
| April | 4 | 0.2% |
| May | 103 | 4.1% |
| June | 273 | 10.8% |
| Julypeak | 541 | 21.4% |
| Augustpeak | 783 | 30.9% |
| Septemberpeak | 702 | 27.7% |
| October | 123 | 4.9% |
| November | 0 | 0% |
| December | 1 | 0% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 2,532 |
In Iowa, September carries 27.7% of the year's monarch butterflies sightings, about 19.4 points above an even month-to-month split. That makes it the 2nd busiest of the twelve months, out of 9 months with recorded activity.
Activity is easing off from August (30.9%) into September, and it heads toward October (4.9%) 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 Iowa 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
- Monarch2,532 records
Plan your monarch butterfly trip in Iowa
Start with live tours near Effigy Mounds National Monument, then compare a nearby stay and a broader wildlife backup before you lock in the trip.
GetYourGuide
Live tours nearbySee live tours near Effigy Mounds National Monument
Use the live GetYourGuide widget to compare local departures and activity styles close to the main monarch butterfly viewing area.
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Compare hotels, cabins and lodges close to the best monarch butterfly viewing area in Iowa.
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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 Iowa in September?+
Yes. September accounts for 702 of the 2,532 verified monarch butterflies sightings logged in Iowa across the year, which is 27.7% of the annual total.
Is September a good time to see monarch butterflies in Iowa?+
September is one of the best months. It ranks 2nd of the year and sits inside the peak window of August, September and July.
What month is best for monarch butterflies in Iowa?+
August is the single busiest month, with the broader peak running through August, September and July, based on 2,532 verified observations.
Which monarch butterflies are you most likely to see in Iowa?+
The most-recorded species in Iowa are Monarch, based on all-time iNaturalist counts.
See monarch butterflies in Iowa in other months
More wildlife in Iowa