Frost dates for WFO Sterling, VA
At WFO Sterling, the median last spring frost (32°F) is Apr 13 and the median first fall frost is Oct 26, for a typical growing season of 195 days. For a 90% chance that the last frost has passed, wait until May 1. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- Apr 13Last spring frost (median)50% chance of 32°F after this date
- May 1Safer planting date10% chance of 32°F after this date
- Oct 26First fall frost (median)50% chance of 32°F by this date
- 195 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 10 | Apr 28 | May 16 |
| 32°F | Mar 29 | Apr 13 | May 1 |
| 28°F | Mar 15 | Mar 31 | Apr 14 |
| 24°F | Mar 2 | Mar 20 | Apr 3 |
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 3 | Oct 16 | Oct 30 |
| 32°F | Oct 11 | Oct 26 | Nov 7 |
| 28°F | Oct 22 | Nov 4 | Nov 22 |
| 24°F | Nov 3 | Nov 17 | Dec 7 |
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 | 151 days | 172 days | 192 days |
| 32°F | 173 days | 195 days | 215 days |
| 28°F | 197 days | 218 days | 241 days |
| 24°F | 219 days | 244 days | 267 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 |
|---|---|---|---|
| 20166 | 7a | 0 to 5°F | 2 km |
| 20148 | 7a | 0 to 5°F | 4 km |
| 20147 | 7a | 0 to 5°F | 7 km |
| 20164 | 7b | 5 to 10°F | 9 km |
| 20105 | 7a | 0 to 5°F | 10 km |
| 20165 | 7b | 5 to 10°F | 12 km |
| 20837 | 7b | 5 to 10°F | 17 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 USC00448084, at 38.9764, -77.4869, elevation 88 m (288 ft).
- Data quality: Standard (24+ years of data), 26 years of freeze data.
- Average days per year at or below 32°F: 119.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Washington DC Dulles Airport (4 km)
- Vienna (19 km)
- Purcellville (27 km)
- Manassas (27 km)
- Mount Wx (36 km)
- Mount Wx 3 (37 km)
- Warrenton 3 SE (41 km)
- Washington Reagan Airport (42 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.