Best Time to See Monarch Butterflies in Delaware
August, September and July is the best time to see monarch butterflies in Delaware. Based on 1,497 verified iNaturalist observations, here is exactly when monarch butterflies are most active across the year in Delaware.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated June 28, 2026.
1,497 verified observations of monarch butterflies in Delaware, recorded across 12 months of the year on iNaturalist.
When monarch butterflies are recorded in Delaware
Peak month
August
460 records (30.7% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 1 | 0.1% |
| February | 1 | 0.1% |
| March | 2 | 0.1% |
| April | 6 | 0.4% |
| May | 66 | 4.4% |
| June | 140 | 9.4% |
| Julypeak | 262 | 17.5% |
| Augustpeak | 460 | 30.7% |
| Septemberpeak | 404 | 27% |
| October | 142 | 9.5% |
| November | 11 | 0.7% |
| December | 2 | 0.1% |
Monarch Butterflies you are most likely to see
| Species | Verified observations |
|---|---|
| Monarch | 1,497 |
Weather to expect, source Open-Meteo
Typical weather in Delaware
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 65 to 86 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 44°F | 32°F | 2.9" |
| Feb | 47°F | 33°F | 3.8" |
| Mar | 54°F | 39°F | 3.8" |
| Apr | 63°F | 48°F | 4.5" |
| May | 70°F | 56°F | 3.9" |
| Jun | 79°F | 66°F | 3.9" |
| Julbest time | 86°F | 73°F | 6" |
| Augbest time | 83°F | 72°F | 5.1" |
| Sepbest time | 77°F | 65°F | 4.3" |
| Oct | 68°F | 55°F | 4.4" |
| Nov | 56°F | 43°F | 2.8" |
| Dec | 48°F | 36°F | 4.8" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Delaware. Weather varies year to year, so treat these as a guide.
More on monarch butterflies in Delaware:
Sightings of monarch butterflies in Delaware peak in August, when 460 of the year's 1,497 verified observations are logged — about 30.7% of the annual total. Activity stays high through August, September and July.
The quietest stretch is January and February, when monarch butterflies are hardest to find — January sees just 1 records. 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 Delaware 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 Delaware
- Captain John Smith Chesapeake National Historic Trail — National Historic Trail
- Chesapeake Bay
- First State National Historical Park — National Historical Park
- Washington-Rochambeau Revolutionary Route National Historic Trail — National Historic Trail
Frequently asked questions
What is the best month to see monarch butterflies in Delaware?+
August is the single best month, and the broader peak window runs through August, September and July, based on 1,497 verified iNaturalist observations.
When are monarch butterflies hardest to see in Delaware?+
January is the quietest month for monarch butterflies in Delaware, with only 1 verified records.
Are monarch butterflies active year-round in Delaware?+
Monarch butterflies are recorded in 12 of 12 months in Delaware, so they can be seen year-round, with a clear peak in August.
More places to see monarch butterflies
More wildlife in Delaware