USDA Hardiness Zone 7b
Frost Dates for 11776 — Port Jefferson Station, New York
NOAA 1991–2020 normals from Mt Sinai, NY (50 ft), 2 miles northeast.
Updated
In Port Jefferson Station, the last spring frost (32°F) is around April 4 in half of years and has passed by April 19 in nine years out of ten. The first fall frost comes around November 7, as early as October 20 one year in ten, leaving a typical freeze-free season of 215 days (NOAA, Mt Sinai, NY).
- Last spring frost
- April 4
- First fall frost
- November 7
- Growing season
- 215 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- December 11
- Last snow
- March 20
- Winters with snow
- 100%
- Snow per year
- 31.8"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Port Jefferson Station
Half of springs at Mt Sinai, NY see their last 32°F night by April 4; only one in ten is past it by March 23, and one in ten still has one after April 19. Planting tender crops after April 10 leaves a 30% risk of a frost on them, after April 13 20%, and after April 19 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 29% of the 173 New York stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 7 in half of years, as early as October 20 one year in ten, and holds off past November 24 one year in ten. A hard freeze of 28°F follows 15 days later, around November 22; in spring the one-in-ten date for 28°F is April 7, 12 days before the 32°F one. The freeze-free season lasts 215 days in a typical year, longer than at 92% of the 173 New York stations; it reaches 236 days one year in ten and falls short of 195 one year in ten. On average 79 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 16 days longer, to about April 20, and return around October 26. Severe cold of 16°F or below comes in 99% of winters, usually between January 1 and February 25.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 6 | Apr 10 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 27 | May 2 | May 7 |
| 32°F | Mar 23 | Mar 29 | Apr 1 | Apr 3 | Apr 4 | Apr 7 | Apr 10 | Apr 13 | Apr 19 |
| 28°F | Mar 11 | Mar 16 | Mar 20 | Mar 24 | Mar 27 | Mar 30 | Apr 1 | Apr 3 | Apr 7 |
| 24°F | Mar 1 | Mar 7 | Mar 11 | Mar 14 | Mar 16 | Mar 20 | Mar 23 | Mar 26 | Mar 31 |
| 20°F | Feb 15 | Feb 25 | Mar 1 | Mar 5 | Mar 8 | Mar 11 | Mar 14 | Mar 18 | Mar 22 |
| 16°F99% of yrs | Jan 28 | Feb 6 | Feb 13 | Feb 20 | Feb 25 | Mar 1 | Mar 5 | Mar 9 | Mar 15 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 10 | Oct 15 | Oct 18 | Oct 22 | Oct 26 | Oct 30 | Nov 2 | Nov 6 | Nov 10 |
| 32°F | Oct 20 | Oct 26 | Oct 30 | Nov 3 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 24 |
| 28°F | Nov 2 | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 9 |
| 24°F | Nov 18 | Nov 25 | Nov 30 | Dec 2 | Dec 6 | Dec 9 | Dec 13 | Dec 18 | Dec 24 |
| 20°F | Dec 1 | Dec 6 | Dec 10 | Dec 15 | Dec 19 | Dec 23 | Dec 27 | Jan 1 | Jan 8 |
| 16°F99% of yrs | Dec 10 | Dec 19 | Dec 25 | Dec 29 | Jan 1 | Jan 5 | Jan 10 | Jan 14 | Jan 22 |
Freeze probabilities 1991–2020 at Mt Sinai, NY, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 11776 →Compare Port Jefferson Station with another place →
Weather by month in Port Jefferson Station
July is the warmest month at Mt Sinai, NY, averaging 83°F by day and 68°F at night; January is the coldest at 41°F and 26°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 70% of years.
Warmth for growing adds up to 3,534 growing degree days a year (base 50°F), more than at 96% of the 173 New York stations. 32% of them (1,129) have built up by the end of June, and July adds the most, 784.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 41 | 26 | 100% | 22 | 5 |
| Feb | 43 | 28 | 100% | 19 | 7 |
| Mar | 50 | 33 | 100% | 15 | 24 |
| Apr | 64 | 43 | 70% | 3 | 145 |
| May | 72 | 51 | 1% | 0 | 359 |
| Jun | 78 | 61 | 0% | 0 | 589 |
| Jul | 83 | 68 | 0% | 0 | 784 |
| Aug | 82 | 67 | 0% | 0 | 756 |
| Sep | 75 | 61 | 0% | 0 | 540 |
| Oct | 65 | 49 | 32% | <1 | 237 |
| Nov | 56 | 40 | 94% | 6 | 73 |
| Dec | 46 | 32 | 100% | 14 | 17 |
Monthly normals 1991–2020 at Mt Sinai, NY (50 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Setauket Strong, NY, 4 miles northwest of Port Jefferson Station, has a last frost 11 days later (April 15), a first frost 3 days later (November 10), a season 7 days shorter.
When it snows in Port Jefferson Station, New York
The first measurable snow (0.1 inch or more) in Port Jefferson Station usually arrives around December 11, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Islip Li Macarthur Airport, NY, 8.5 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 15 days after the last snow.
Planting calendar for 11776
| When | What to do |
|---|---|
| January 24 – February 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 7 – February 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 7 – March 21 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 4 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 15 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 7 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 11776 is 2 miles from Mt Sinai, NY, which stands at 50 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 11727 (Coram). The 2023 USDA Plant Hardiness Zone Map lists ZIP 11776 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.