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Will it freeze in Port Jefferson in the next 7 nights?
No overnight lows at or below 32°F are forecast in Port Jefferson during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 60°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.
- Tonight 60°F Above 36°F · Light Rain then Showers And Thunderstorms Likely
- Fri, Nov 6 54°F Above 36°F · Light Rain
- Sat, Nov 7 45°F Above 36°F · Chance Light Rain
- Sun, Nov 8 43°F Above 36°F · Mostly Clear
- Mon, Nov 9 43°F Above 36°F · Mostly Clear
- Tue, Nov 10 43°F Above 36°F · Mostly Clear
- Wed, Nov 11 40°F Above 36°F · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Port Jefferson
The median first fall hard-freeze date (28°F) is November 22, from NOAA’s 1991–2020 Climate Normals at Mt Sinai. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 6 · Apr 20 · May 7 | Oct 10 · Oct 26 · Nov 10 | 187 days |
| 32°F freeze | Mar 23 · Apr 4 · Apr 19 | Oct 20 · Nov 7 · Nov 24 | 215 days |
| 28°F hard freeze | Mar 11 · Mar 27 · Apr 7 | Nov 2 · Nov 22 · Dec 9 | 241 days |
Average high temperature by month
1991–2020 normals at Mt Sinai
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Port Jefferson, NY come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Mt Sinai (station USC00305606, elevation 50 ft), 1.9 mi from Port Jefferson. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Port Jefferson
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Lake Grove, NY | 6.8 mi | Apr 10 | Nov 2 |
| Patchogue, NY | 12 mi | Apr 4 | Nov 11 |
| Northport, NY | 16 mi | Apr 9 | Nov 10 |
| Bridgeport, CT | 19 mi | Apr 5 | Nov 6 |
| Milford, CT | 19 mi | Apr 5 | Nov 6 |
| Norwalk, CT | 22 mi | Apr 17 | Oct 23 |
| Babylon, NY | 22 mi | Apr 6 | Nov 6 |
| West Haven, CT | 23 mi | Apr 17 | Oct 27 |
| Lindenhurst, NY | 24 mi | Apr 6 | Nov 6 |
| Farmingdale, NY | 25 mi | Apr 6 | Nov 6 |
Frequently asked questions
When is the last frost in Port Jefferson?
On average, the last spring frost (32°F) in Port Jefferson is around April 4. In about 1 year in 10 it comes after April 19, and in 9 years in 10 it comes after March 23.
When is the first frost in Port Jefferson?
The first fall frost (32°F) usually arrives around November 7. There’s a 10% chance of a freeze by October 20 and a 90% chance by November 24.
Can it frost in Port Jefferson after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 20.
What growing zone is Port Jefferson?
Port Jefferson is in USDA Plant Hardiness Zone 7b (average annual extreme minimum temperature 5 to 10°F), based on the 2023 USDA map for ZIP code 11777. See growing zones in New York.
More: all New York frost dates · New York growing zones · frost vs. freeze