Alton, NH Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Alton, a community in Belknap County, New Hampshire.
Today
73°F
Mostly Sunny
Mostly sunny. High near 73, with temperatures falling to around 67 in the afternoon. Southwest wind around 5 mph.
7-day forecast for Alton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 73°F | Mostly Sunny | 5 mph SW | 3% |
| Tonight | 53°F | Partly Cloudy | 5 mph SW | 2% |
| Thursday | 69°F | Mostly Cloudy then Light Rain Likely | 5 to 10 mph SW | 57% |
| Thursday Night | 57°F | Chance Light Rain | 5 to 10 mph SW | 27% |
| Friday | 67°F | Light Rain Likely | 0 to 5 mph SW | 59% |
| Friday Night | 52°F | Light Rain | 0 to 5 mph NE | 83% |
| Saturday | 60°F | Light Rain Likely | 5 mph NE | 72% |
| Saturday Night | 43°F | Chance Light Rain | 5 to 10 mph N | 40% |
| Sunday | 54°F | Chance Light Rain | 5 to 10 mph NW | 34% |
| Sunday Night | 36°F | Partly Cloudy | 5 mph W | 7% |
| Monday | 51°F | Mostly Sunny | 5 to 15 mph W | 13% |
| Monday Night | 33°F | Partly Cloudy | 5 to 10 mph W | 12% |
| Tuesday | 53°F | Mostly Sunny | 10 to 15 mph W | 8% |
| Tuesday Night | 33°F | Partly Cloudy | 5 to 10 mph W | 8% |
Forecast source: National Weather Service (api.weather.gov) for Alton (43.456, -71.222). Updated through the day.
Growing snapshot for Alton
Last spring frost
Apr 30
First fall frost
Oct 18
Growing season
170 days
Hardiness zone
5b
More local growing data for Alton: nearby ZIP 03809 weather · frost dates · planting calendar · New Hampshire frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Lakeport 2, Nh (14.5 mi from Alton). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.