Frost dates for Franklin Falls Dam, NH
At Franklin Falls Dam, the median last spring frost (32°F) is May 7 and the median first fall frost is Oct 3, for a typical growing season of 148 days. For a 90% chance that the last frost has passed, wait until May 20. Nearby ZIP codes are in USDA hardiness zone 5b.
- May 7Last spring frost (median)50% chance of 32°F after this date
- May 20Safer planting date10% chance of 32°F after this date
- Oct 3First fall frost (median)50% chance of 32°F by this date
- 148 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 | May 7 | May 20 | Jun 1 |
| 32°F | Apr 27 | May 7 | May 20 |
| 28°F | Apr 15 | Apr 27 | May 7 |
| 24°F | Apr 3 | Apr 14 | Apr 25 |
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 | Sep 14 | Sep 27 | Oct 6 |
| 32°F | Sep 24 | Oct 3 | Oct 15 |
| 28°F | Oct 1 | Oct 13 | Oct 29 |
| 24°F | Oct 10 | Oct 25 | Nov 9 |
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 | 111 days | 128 days | 143 days |
| 32°F | 132 days | 148 days | 163 days |
| 28°F | 152 days | 169 days | 188 days |
| 24°F | 176 days | 193 days | 211 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 |
|---|---|---|---|
| 03235 | 5b | -15 to -10°F | 3 km |
| 03276 | 5b | -15 to -10°F | 8 km |
| 03269 | 5b | -15 to -10°F | 8 km |
| 03231 | 5b | -15 to -10°F | 8 km |
| 03216 | 5b | -15 to -10°F | 11 km |
| 03243 | 5b | -15 to -10°F | 11 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 USC00273182, at 43.4703, -71.6536, elevation 137 m (450 ft).
- Data quality: Estimated from nearby stations (2+ years), 9 years of freeze data.
- Average days per year at or below 32°F: 174.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Salisbury (15 km)
- Lakeport 2 (18 km)
- Grafton (26 km)
- Meredith 3 NNE (29 km)
- Hopkinton Lake (32 km)
- Concord Muni Airport (33 km)
- Plymouth (35 km)
- Bradford 2 (37 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.