Whales in Delaware in September
Yes, September is a good month to see whales in Delaware. It is the 6th busiest month of the year, with 23 of the 254 sightings logged across the year (9.1%), 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.
Humpback Whale · botanygirl CC BY
Humpback Whale · Public domain CC0
Tamanend's Bottlenose Dolphin · inbetweenbays CC BY
Good month for whales in Delaware
9.1%
of yearly sightings
23
records in September
#6
busiest month of 12
254
verified records a year
August 18.9%, September 9.1%, October 13.4%. Busiest month is August at 18.9%.
254 verified observations of whales in Delaware, recorded across 12 months of the year on iNaturalist.
When whales are recorded in Delaware
Peak month
August
48 records (18.9% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 2 | 0.8% |
| February | 2 | 0.8% |
| March | 11 | 4.3% |
| April | 19 | 7.5% |
| Maypeak | 36 | 14.2% |
| June | 29 | 11.4% |
| Julypeak | 46 | 18.1% |
| Augustpeak | 48 | 18.9% |
| September | 23 | 9.1% |
| October | 34 | 13.4% |
| November | 2 | 0.8% |
| December | 2 | 0.8% |
Whales you are most likely to see
| Species | Verified observations |
|---|---|
| Tamanend's Bottlenose Dolphin | 217 |
| Humpback Whale | 12 |
| Fin Whale | 2 |
| Common Dolphin | 1 |
In Delaware, September carries 9.1% of the year's whales sightings, about 0.8 points above an even month-to-month split. That makes it the 6th busiest of the twelve months, out of 12 months with recorded activity.
Activity is easing off from August (18.9%) into September, and it heads toward October (13.4%) after. The busiest month is August (18.9%), so if timing is flexible, that window is the safer bet.
The whales most often recorded in Delaware are Tamanend's Bottlenose Dolphin, Humpback Whale and Fin Whale. 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 whales you are most likely to see
- Tamanend's Bottlenose Dolphin217 records
- Humpback Whale12 records
- Fin Whale2 records
- Common Dolphin1 records
Frequently asked questions
Can you see whales in Delaware in September?+
Yes. September accounts for 23 of the 254 verified whales sightings logged in Delaware across the year, which is 9.1% of the annual total.
Is September a good time to see whales in Delaware?+
September is the 6th busiest month. It is workable, though August and July is the stronger window for a reliable sighting.
What month is best for whales in Delaware?+
August is the single busiest month, with the broader peak running through August, July and May, based on 254 verified observations.
Which whales are you most likely to see in Delaware?+
The most-recorded species in Delaware are Tamanend's Bottlenose Dolphin, Humpback Whale and Fin Whale, based on all-time iNaturalist counts.
See whales in Delaware in other months
More wildlife in Delaware