Harman US

Northumberland, PA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Northumberland, a borough in Northumberland County, Pennsylvania.

This Afternoon
73°F
Partly Sunny
Partly sunny, with a high near 73. Southeast wind around 2 mph.

7-day forecast for Northumberland

WhenTempForecastWindPrecip
This Afternoon 73°F Partly Sunny 2 mph SE 2%
Tonight 59°F Rain Showers 1 to 8 mph SE 83%
Sunday 72°F Rain Showers 3 to 9 mph S 95%
Sunday Night 53°F Showers And Thunderstorms 3 to 8 mph NW 91%
Monday 68°F Mostly Cloudy 7 mph N 7%
Monday Night 49°F Chance Rain Showers 5 mph NE 41%
Tuesday 62°F Chance Rain Showers 5 mph NE 45%
Tuesday Night 47°F Chance Rain Showers 6 mph E 36%
Wednesday 62°F Chance Rain Showers 7 mph E 36%
Wednesday Night 47°F Chance Rain Showers 6 mph NE 35%
Thursday 63°F Chance Rain Showers 6 mph NE 35%
Thursday Night 47°F Chance Rain Showers 5 mph NE 34%
Friday 67°F Chance Rain Showers 3 to 7 mph N 25%
Friday Night 48°F Slight Chance Rain Showers 6 mph N 23%

Forecast source: National Weather Service (api.weather.gov) for Northumberland (40.897, -76.793). Updated through the day.

Growing snapshot for Northumberland

Last spring frost
Apr 30
First fall frost
Oct 13
Growing season
166 days
Hardiness zone
6b

More local growing data for Northumberland: nearby ZIP 17857 weather · frost dates · planting calendar · Pennsylvania frost dates

Nearby towns & communities

All Pennsylvania locations ›

Climate data from the nearest NOAA station, Sunbury, Pa (5.5 mi from Northumberland). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.