Frost dates for Upper Marlboro 3 NNW, MD
At Upper Marlboro 3 NNW, the median last spring frost (32°F) is Apr 9 and the median first fall frost is Oct 29, for a typical growing season of 203 days. For a 90% chance that the last frost has passed, wait until Apr 24. Nearby ZIP codes are in USDA hardiness zones 7b to 8a.
- Apr 9Last spring frost (median)50% chance of 32°F after this date
- Apr 24Safer planting date10% chance of 32°F after this date
- Oct 29First fall frost (median)50% chance of 32°F by this date
- 203 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 8 | Apr 24 | May 12 |
| 32°F | Mar 27 | Apr 9 | Apr 24 |
| 28°F | Mar 14 | Mar 30 | Apr 12 |
| 24°F | Mar 1 | Mar 18 | 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 5 | Oct 19 | Nov 1 |
| 32°F | Oct 14 | Oct 29 | Nov 11 |
| 28°F | Oct 27 | Nov 10 | Nov 25 |
| 24°F | Nov 8 | Nov 23 | Dec 11 |
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 | 156 days | 178 days | 198 days |
| 32°F | 182 days | 203 days | 222 days |
| 28°F | 207 days | 225 days | 245 days |
| 24°F | 229 days | 250 days | 274 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 |
|---|---|---|---|
| 20774 | 7b | 5 to 10°F | 3 km |
| 20772 | 7b | 5 to 10°F | 8 km |
| 20762 | 7b | 5 to 10°F | 10 km |
| 20747 | 7b | 5 to 10°F | 10 km |
| 20711 | 7b | 5 to 10°F | 12 km |
| 20623 | 7b | 5 to 10°F | 14 km |
| 20754 | 7b | 5 to 10°F | 16 km |
| 20778 | 8a | 10 to 15°F | 17 km |
| 20751 | 8a | 10 to 15°F | 19 km |
| 20779 | 8a | 10 to 15°F | 20 km |
| 20758 | 7b | 5 to 10°F | 20 km |
| 20613 | 7b | 5 to 10°F | 20 km |
| 20736 | 7b | 5 to 10°F | 22 km |
| 20714 | 8a | 10 to 15°F | 26 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 USC00189070, at 38.8519, -76.7683, elevation 40 m (130 ft).
- Data quality: Representative (10+ years), 19 years of freeze data.
- Average days per year at or below 32°F: 103.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Glenn Dale Bell Station (13 km)
- National Arboretum DC (19 km)
- Oxon Hill (21 km)
- Beltsville (24 km)
- Annapolis Police Brks (28 km)
- Laurel 3 W (28 km)
- Annapolis Naf (30 km)
- Dalecarlia Rsvr (31 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.