Port Jefferson, NY Weather & Climate Normals
What a normal year in Port Jefferson actually looks like
On the 30-year record NOAA keeps for Port Jefferson, NY, the comfort score comes out to 51/100, strongly seasonal: Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. Only 5 months a year land in the 55–75°F range this site treats as mild.
How much Port Jefferson's weather actually swings
Average temperatures in Port Jefferson run from 34°F in Jan up to 75°F in Jul, a 41.6°F seasonal swing, a middling gap by national standards.
Port Jefferson, month by month
| Month | Avg high | Avg low | Precip |
|---|---|---|---|
| Jan | 41°F | 26°F | 3.71in |
| Feb | 43°F | 28°F | 3.2in |
| Mar | 50°F | 33°F | 4.65in |
| Apr | 64°F | 43°F | 4.42in |
| May | 72°F | 51°F | 3.89in |
| Jun | 78°F | 61°F | 3.93in |
| Jul | 83°F | 68°F | 3.88in |
| Aug | 82°F | 67°F | 4.02in |
| Sep | 75°F | 61°F | 4.3in |
| Oct | 65°F | 49°F | 4.24in |
| Nov | 56°F | 40°F | 3.7in |
| Dec | 46°F | 32°F | 4.56in |
If you're timing a visit, May, Jun, Aug, Sep, and Oct are Port Jefferson's mildest stretch; if you're moving there, you should plan around Jul's heat and Jan's cold instead.
How wet Port Jefferson actually gets
Port Jefferson averages 48.5in of precipitation a year across roughly 0 days with measurable rain or snow; the nearest NOAA station does not record snowfall, so no snow figure is shown rather than guessed.
Port Jefferson against the rest of the country
Out of 4876 cities scored here, Port Jefferson comes in at 1574; within NY alone it ranks 19 of 170. Population is about 8,189.
Checking the actual forecast
These figures come from Mt Sinai, NY US, the NOAA station 1.9 miles from Port Jefferson, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why some cities show no snow or rain figure · What a 30-year climate normal actually is