Best Time to See Jellyfishes in New Jersey
July, August and June is the best time to see jellyfishes in New Jersey. Based on 763 verified iNaturalist observations, here is exactly when jellyfishes are most active across the year in New Jersey.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated July 2, 2026.
Mushroom Jelly · Samuel Paul Galick CC BY
Bay Nettle · donbull CC BY
Dwarf Lion's Mane Jelly · gwt2102 CC BY
763 verified observations of jellyfishes in New Jersey, recorded across 12 months of the year on iNaturalist.
When jellyfishes are recorded in New Jersey
Peak month
July
286 records (37.5% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 3 | 0.4% |
| February | 3 | 0.4% |
| March | 11 | 1.4% |
| April | 27 | 3.5% |
| May | 18 | 2.4% |
| Junepeak | 127 | 16.6% |
| Julypeak | 286 | 37.5% |
| Augustpeak | 142 | 18.6% |
| September | 58 | 7.6% |
| October | 59 | 7.7% |
| November | 24 | 3.1% |
| December | 5 | 0.7% |
Jellyfishes you are most likely to see
| Species | Verified observations |
|---|---|
| Mushroom Jelly | 240 |
| Bay Nettle | 144 |
| Dwarf Lion's Mane Jelly | 76 |
| Atlantic Sea Nettle | 30 |
| Atlantic Lion's Mane Jelly | 23 |
| Mauve Stinger | 19 |
| Cannonball Jelly | 15 |
| Common Moon Jelly | 14 |
Weather to expect, source Open-Meteo
Typical weather in New Jersey
Recent typical conditions by month, so you can plan a trip around both when jellyfishes are active and what the weather is doing. The best months to look for jellyfishes sit around 63 to 88 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 43°F | 28°F | 3.4" |
| Feb | 45°F | 29°F | 3.5" |
| Mar | 54°F | 35°F | 4.3" |
| Apr | 63°F | 44°F | 4.6" |
| May | 72°F | 53°F | 4.1" |
| Junbest time | 82°F | 63°F | 4.1" |
| Julbest time | 88°F | 70°F | 5.2" |
| Augbest time | 85°F | 69°F | 4.3" |
| Sep | 78°F | 61°F | 4.4" |
| Oct | 68°F | 52°F | 4.7" |
| Nov | 55°F | 39°F | 3" |
| Dec | 46°F | 32°F | 4.6" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for New Jersey. Weather varies year to year, so treat these as a guide.
Sightings of jellyfishes in New Jersey peak in July, when 286 of the year's 763 verified observations are logged — about 37.5% of the annual total. Activity stays high through July, August and June.
The quietest stretch is January and February, when jellyfishes are hardest to find — January sees just 3 records. If a reliable sighting matters, plan around the peak window rather than the off-season.
The jellyfishes you are most likely to encounter in New Jersey are Mushroom Jelly, Bay Nettle and Dwarf Lion's Mane Jelly — 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 jellyfishes in New Jersey
- Appalachian National Scenic Trail — National Scenic Trail
- Delaware Water Gap National Recreation Area — National Recreation Area
- Great Egg Harbor River
- Morristown National Historical Park — National Historical Park
- Ellis Island Part of Statue of Liberty National Monument — Part of Statue of Liberty National Monument
- Gateway National Recreation Area — National Recreation Area
Frequently asked questions
What is the best month to see jellyfishes in New Jersey?+
July is the single best month, and the broader peak window runs through July, August and June, based on 763 verified iNaturalist observations.
When are jellyfishes hardest to see in New Jersey?+
January is the quietest month for jellyfishes in New Jersey, with only 3 verified records.
Are jellyfishes active year-round in New Jersey?+
Jellyfishes are recorded in 12 of 12 months in New Jersey, so they can be seen year-round, with a clear peak in July.
More places to see jellyfishes
More wildlife in New Jersey