Frost dates for Islip Li Macarthur Airport, NY
At Islip Li Macarthur Airport, the median last spring frost (32°F) is Apr 10 and the median first fall frost is Nov 2, for a typical growing season of 207 days. For a 90% chance that the last frost has passed, wait until Apr 25. Nearby ZIP codes are in USDA hardiness zone 7b.
- Apr 10Last spring frost (median)50% chance of 32°F after this date
- Apr 25Safer planting date10% chance of 32°F after this date
- Nov 2First fall frost (median)50% chance of 32°F by this date
- 207 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 11 | Apr 23 | May 7 |
| 32°F | Mar 31 | Apr 10 | Apr 25 |
| 28°F | Mar 14 | Mar 30 | Apr 12 |
| 24°F | Mar 1 | Mar 17 | Mar 31 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 8 | Oct 21 | Nov 4 |
| 32°F | Oct 18 | Nov 2 | Nov 15 |
| 28°F | Nov 1 | Nov 14 | Dec 1 |
| 24°F | Nov 11 | Nov 27 | Dec 12 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 162 days | 182 days | 199 days |
| 32°F | 188 days | 207 days | 223 days |
| 28°F | 211 days | 230 days | 250 days |
| 24°F | 231 days | 253 days | 275 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 11779 | 7b | 5 to 10°F | 2 km |
| 11741 | 7b | 5 to 10°F | 3 km |
| 11716 | 7b | 5 to 10°F | 3 km |
| 11742 | 7b | 5 to 10°F | 5 km |
| 11749 | 7b | 5 to 10°F | 6 km |
| 11767 | 7b | 5 to 10°F | 7 km |
| 11755 | 7b | 5 to 10°F | 7 km |
| 11738 | 7b | 5 to 10°F | 7 km |
| 11752 | 7b | 5 to 10°F | 7 km |
| 11722 | 7b | 5 to 10°F | 8 km |
| 11720 | 7b | 5 to 10°F | 9 km |
| 11788 | 7b | 5 to 10°F | 10 km |
| 11787 | 7b | 5 to 10°F | 11 km |
| 11717 | 7b | 5 to 10°F | 13 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00004781, at 40.7939, -73.1017, elevation 26 m (84 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 98.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Molloy Cercom (8 km)
- Mount Sinai (17 km)
- Setauket Strong (18 km)
- Shirley Brookhaven Airport (20 km)
- Upton COOP - Nwsfo New York (22 km)
- Centerport (25 km)
- Farmingdale Airport (27 km)
- Baiting Hollow (34 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.