Portsmouth, NH Weather & Growing Conditions
Today
76°F
Mostly Sunny
Mostly sunny. High near 76, with temperatures falling to around 68 in the afternoon. Southwest wind 5 to 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 76°F | Mostly Sunny | 5 to 10 mph SW | 3% |
| Tonight | 56°F | Partly Cloudy | 5 to 10 mph SW | 2% |
| Thursday | 75°F | Mostly Cloudy then Chance Light Rain | 5 to 15 mph SW | 36% |
| Thursday Night | 60°F | Mostly Cloudy then Chance Light Rain | 5 to 10 mph SW | 39% |
| Friday | 71°F | Light Rain | 5 mph S | 79% |
| Friday Night | 54°F | Light Rain | 5 mph E | 92% |
| Saturday | 64°F | Light Rain | 5 to 10 mph NE | 79% |
| Saturday Night | 44°F | Chance Light Rain | 5 to 10 mph N | 35% |
| Sunday | 58°F | Chance Light Rain | 5 to 10 mph W | 30% |
| Sunday Night | 36°F | Partly Cloudy | 5 mph W | 8% |
| Monday | 55°F | Mostly Sunny then Slight Chance Light Rain | 10 to 15 mph W | 16% |
| Monday Night | 33°F | Slight Chance Light Rain then Partly Cloudy | 10 mph W | 15% |
| Tuesday | 58°F | Mostly Sunny | 10 to 15 mph W | 9% |
| Tuesday Night | 33°F | Partly Cloudy | 10 mph W | 8% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Portsmouth, NH
Last spring frost
May 4
First fall frost
Oct 8
Growing season
157 days
Hardiness zone
6a
Explore more for Portsmouth, NH: full frost dates · planting calendar · New Hampshire frost dates
Climate data from the nearest NOAA station, Greenland, Nh (3.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.