Frost dates for 20101Dulles, VA
The average last spring frost in Dulles is April 13 and the average first fall frost is October 26, giving a typical growing season of about 195 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 13
- Average first fall frost
- Oct 26
- Growing season
- 195 days
Safer after May 1 (1-in-10 risk)
Possible by Oct 11 (1-in-10 risk)
Last frost typically in 161 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 10 · Apr 28 · May 16 | Oct 3 · Oct 16 · Oct 30 | 172 days | 100% |
| Frost / freeze (32°F) | Mar 29 · Apr 13 · May 1 | Oct 11 · Oct 26 · Nov 7 | 195 days | 100% |
| Hard freeze (28°F) | Mar 15 · Mar 31 · Apr 14 | Oct 22 · Nov 4 · Nov 22 | 218 days | 100% |
Planting calendar for Dulles
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 13 – May 19 |
| Tomatoes | Transplant outdoors | Apr 29 – Jul 6 |
| Peppers | Start seeds indoors | Mar 13 – Apr 13 |
| Peppers | Transplant outdoors | May 13 – Jun 13 |
| Eggplant | Start seeds indoors | Mar 30 – Apr 28 |
| Eggplant | Transplant outdoors | May 13 – Jun 13 |
| Cucumbers | Sow outdoors | May 13 – Jul 16 |
| Summer squash | Sow outdoors | Apr 29 – Jun 13 |
| Winter squash & pumpkins | Sow outdoors | May 13 – Jun 13 |
| Snap beans | Sow outdoors | Apr 29 – Aug 8 |
| Sweet corn | Sow outdoors | Apr 29 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 13 – Jun 13 |
| Okra | Sow outdoors | May 6 – May 29 |
| Peas | Sow outdoors (spring) | Mar 13 – Apr 28 |
| Potatoes | Plant outdoors (spring) | Mar 13 – May 13 |
| Onions | Start seeds indoors (spring) | Jan 30 – Feb 26 |
| Onions | Transplant outdoors (spring) | Mar 30 – Apr 28 |
| Broccoli | Start seeds indoors (spring) | Feb 23 – Mar 29 |
| Broccoli | Transplant outdoors (spring) | Mar 30 – Apr 28 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 13 – Mar 13 |
| Cabbage | Transplant outdoors (spring) | Mar 13 – Apr 13 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 13 – May 29 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 6 – Apr 19 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 13 – May 3 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Mar 30 – Apr 19 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 13 – May 29 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 20101 is matched to the NOAA station Wfo Sterling, VA, 4.8 km away, at 288 ft elevation (35 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wfo Sterling, VA (used) | 288 ft | Apr 13 | Oct 26 |
| Washington Dc Dulles Ap, VA | 290 ft | Apr 15 | Oct 24 |
| Vienna, VA | 418 ft | Apr 14 | Oct 29 |
| Rockville 1 Ne, MD | 440 ft | Apr 1 | Nov 6 |
Frost dates near Dulles
- Dulles, VA 20189 · last Apr 13, first Oct 26
- Sterling, VA 20163 · last Apr 13, first Oct 26
- Dhs, VA 20598 · last Apr 13, first Oct 26
- Ashburn, VA 20147 · last Apr 13, first Oct 26
- Herndon, VA 20172 · last Apr 15, first Oct 24
- Reston, VA 20194 · last Apr 14, first Oct 29
- Great Falls, VA 22066 · last Apr 14, first Oct 29
- Chantilly, VA 20151 · last Apr 15, first Oct 24
Frequently asked questions
- When is the last frost in Dulles, VA?
- For ZIP code 20101, the average last spring frost (32°F) is April 13, based on NOAA 1991-2020 climate normals for the Wfo Sterling, VA weather station. There is a 1-in-10 chance of a frost after May 1.
- When is the first frost in Dulles, VA?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 11, so tender plants are at risk from that point on.
- How long is the growing season in 20101?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 195 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.