USDA Hardiness Zone 7b
Frost Dates for 11751 — Islip, New York
NOAA 1991–2020 normals from Molloy Cercom, NY (5 ft), 7 miles east.
Updated
In Islip, the last spring frost (32°F) is around April 4 in half of years and has passed by April 21 in nine years out of ten. The first fall frost comes around November 11, as early as October 27 one year in ten, leaving a typical freeze-free season of 219 days (NOAA, Molloy Cercom, NY).
- Last spring frost
- April 4
- First fall frost
- November 11
- Growing season
- 219 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 Islip
Half of springs at Molloy Cercom, NY see their last 32°F night by April 4; only one in ten is past it by March 22, and one in ten still has one after April 21. Planting tender crops after April 10 leaves a 30% risk of a frost on them, after April 14 20%, and after April 21 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 90% of the 173 New York stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 11 in half of years, as early as October 27 one year in ten, and holds off past November 29 one year in ten. A hard freeze of 28°F follows 13 days later, around November 24; in spring the one-in-ten date for 28°F is April 5, 16 days before the 32°F one. The freeze-free season lasts 219 days in a typical year, longer than at 94% of the 173 New York stations; it reaches 241 days one year in ten and falls short of 197 one year in ten. On average 76 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 30. Severe cold of 16°F or below comes in 98% of winters, usually between January 2 and February 19.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Apr 9 | Apr 13 | Apr 17 | Apr 20 | Apr 24 | Apr 28 | May 2 | May 8 |
| 32°F | Mar 22 | Mar 28 | Mar 31 | Apr 2 | Apr 4 | Apr 7 | Apr 10 | Apr 14 | Apr 21 |
| 28°F | Mar 9 | Mar 15 | Mar 19 | Mar 22 | Mar 24 | Mar 27 | Mar 30 | Apr 1 | Apr 5 |
| 24°F | Feb 27 | Mar 4 | Mar 8 | Mar 11 | Mar 14 | Mar 17 | Mar 21 | Mar 25 | Mar 29 |
| 20°F | Feb 11 | Feb 21 | Feb 26 | Mar 1 | Mar 4 | Mar 8 | Mar 12 | Mar 15 | Mar 22 |
| 16°F98% of yrs | Jan 25 | Feb 3 | Feb 8 | Feb 13 | Feb 19 | Feb 24 | Feb 28 | Mar 5 | Mar 11 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 15 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 13 |
| 32°F | Oct 27 | Oct 31 | Nov 3 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 22 | Nov 29 |
| 28°F | Nov 6 | Nov 12 | Nov 16 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 5 | Dec 12 |
| 24°F | Nov 18 | Nov 25 | Dec 1 | Dec 4 | Dec 7 | Dec 10 | Dec 14 | Dec 19 | Dec 26 |
| 20°F | Dec 2 | Dec 7 | Dec 12 | Dec 16 | Dec 21 | Dec 24 | Dec 28 | Jan 2 | Jan 10 |
| 16°F98% of yrs | Dec 13 | Dec 20 | Dec 26 | Dec 30 | Jan 2 | Jan 7 | Jan 12 | Jan 17 | Jan 26 |
Freeze probabilities 1991–2020 at Molloy Cercom, 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 11751 →Compare Islip with another place →
Compared with the next station
The nearest other station, Islip Li Macarthur Airport, NY, 7 miles northeast of Islip, has a last frost 6 days later (April 10), a first frost 9 days earlier (November 2), a season 12 days shorter.
When it snows in Islip, New York
The first measurable snow (0.1 inch or more) in Islip 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, 7.2 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 11751
| 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 19 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 28 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 11 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 11751 is 7 miles from Molloy Cercom, NY, which stands at 5 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 11782 (Sayville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 11751 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.