Frost dates for 11794Stony Brook, NY
The average last spring frost in Stony Brook is April 10 and the average first fall frost is November 2, giving a typical growing season of about 207 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 10
- Average first fall frost
- Nov 2
- Growing season
- 207 days
Safer after Apr 25 (1-in-10 risk)
Possible by Oct 18 (1-in-10 risk)
Last frost typically in 158 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 11 · Apr 23 · May 7 | Oct 8 · Oct 21 · Nov 4 | 182 days | 100% |
| Frost / freeze (32°F) | Mar 31 · Apr 10 · Apr 25 | Oct 18 · Nov 2 · Nov 15 | 207 days | 100% |
| Hard freeze (28°F) | Mar 14 · Mar 30 · Apr 12 | Nov 1 · Nov 14 · Dec 1 | 230 days | 100% |
Planting calendar for Stony Brook
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 10 – May 16 |
| Tomatoes | Transplant outdoors | Apr 26 – Jul 13 |
| Peppers | Start seeds indoors | Mar 10 – Apr 10 |
| Peppers | Transplant outdoors | May 10 – Jun 10 |
| Eggplant | Start seeds indoors | Mar 27 – Apr 25 |
| Eggplant | Transplant outdoors | May 10 – Jun 10 |
| Cucumbers | Sow outdoors | May 10 – Jul 23 |
| Summer squash | Sow outdoors | Apr 26 – Jun 10 |
| Winter squash & pumpkins | Sow outdoors | May 10 – Jun 10 |
| Snap beans | Sow outdoors | Apr 26 – Aug 15 |
| Sweet corn | Sow outdoors | Apr 26 – Jul 13 |
| Watermelon & cantaloupe | Sow outdoors | May 10 – Jun 10 |
| Okra | Sow outdoors | May 3 – May 26 |
| Peas | Sow outdoors (spring) | Mar 10 – Apr 25 |
| Potatoes | Plant outdoors (spring) | Mar 10 – May 10 |
| Onions | Start seeds indoors (spring) | Jan 27 – Feb 23 |
| Onions | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (spring) | Feb 20 – Mar 26 |
| Broccoli | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (fall) | Jul 3 – Jul 13 |
| Broccoli | Transplant outdoors (fall) | Aug 2 – Aug 13 |
| Cabbage | Start seeds indoors (spring) | Feb 10 – Mar 10 |
| Cabbage | Transplant outdoors (spring) | Mar 10 – Apr 10 |
| Cabbage | Start seeds indoors (fall) | Jun 23 – Jul 23 |
| Cabbage | Transplant outdoors (fall) | Jul 23 – Aug 23 |
| Leaf lettuce | Sow outdoors (spring) | Mar 10 – May 26 |
| Leaf lettuce | Sow outdoors (fall) | Jul 23 – Sep 8 |
| Spinach | Sow outdoors (spring) | Mar 3 – Apr 16 |
| Spinach | Sow outdoors (fall) | Aug 9 – Sep 13 |
| Radishes | Sow outdoors (spring) | Mar 10 – Apr 30 |
| Radishes | Sow outdoors (fall) | Jul 23 – Sep 23 |
| Kale | Sow outdoors (spring) | Mar 27 – Apr 16 |
| Kale | Sow outdoors (fall) | Jul 16 – Aug 23 |
| Carrots | Sow outdoors (spring) | Apr 10 – May 26 |
| Carrots | Sow outdoors (fall) | Jun 23 – Aug 8 |
| Garlic | Plant outdoors (fall) | Oct 23 – Nov 23 |
Where these dates come from
ZIP code 11794 is matched to the NOAA station Islip Li Macarthur Ap, NY, 15 km away, at 84 ft elevation (5 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Islip Li Macarthur Ap, NY (used) | 84 ft | Apr 10 | Nov 2 |
| Setauket Strong, NY | 40 ft | Apr 15 | Nov 10 |
| Mt Sinai, NY | 50 ft | Apr 4 | Nov 7 |
| Centerport, NY | 30 ft | Apr 9 | Nov 10 |
Frost dates near Stony Brook
- Stony Brook, NY 11790 · last Apr 10, first Nov 2
- East Setauket, NY 11733 · last Apr 15, first Nov 10
- Saint James, NY 11780 · last Apr 10, first Nov 2
- Port Jefferson, NY 11777 · last Apr 10, first Nov 2
- Centereach, NY 11720 · last Apr 10, first Nov 2
- Lake Grove, NY 11755 · last Apr 10, first Nov 2
- Port Jefferson Station, NY 11776 · last Apr 10, first Nov 2
- Nesconset, NY 11767 · last Apr 10, first Nov 2
Frequently asked questions
- When is the last frost in Stony Brook, NY?
- For ZIP code 11794, the average last spring frost (32°F) is April 10, based on NOAA 1991-2020 climate normals for the Islip Li Macarthur Ap, NY weather station. There is a 1-in-10 chance of a frost after April 25.
- When is the first frost in Stony Brook, NY?
- The average first fall frost (32°F) is November 2. There is a 1-in-10 chance of frost by October 18, so tender plants are at risk from that point on.
- How long is the growing season in 11794?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 207 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.