Alton, NH Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Alton, a community in Belknap County, New Hampshire.
Today
82°F
Sunny
Sunny, with a high near 82. West wind 5 to 10 mph.
7-day forecast for Alton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 82°F | Sunny | 5 to 10 mph W | 0% |
| Tonight | 61°F | Mostly Clear | 0 to 5 mph W | 0% |
| Wednesday | 84°F | Mostly Sunny | 0 to 5 mph SW | 0% |
| Wednesday Night | 66°F | Mostly Cloudy | 0 to 5 mph SW | 5% |
| Thursday | 86°F | Mostly Sunny then Chance Showers And Thunderstorms | 0 to 5 mph SW | 44% |
| Thursday Night | 69°F | Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph SW | 40% |
| Friday | 87°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph W | 23% |
| Friday Night | 68°F | Slight Chance Showers And Thunderstorms | 0 to 5 mph W | 22% |
| Saturday | 85°F | Chance Rain Showers then Chance Showers And Thunderstorms | 0 to 5 mph W | 44% |
| Saturday Night | 67°F | Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph W | 39% |
| Sunday | 86°F | Sunny | 0 to 10 mph W | 8% |
| Sunday Night | 68°F | Mostly Clear | 0 to 5 mph W | 7% |
| Monday | 86°F | Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph W | 16% |
| Monday Night | 65°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 to 10 mph W | 16% |
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 Aug 4, 2026.