Irwin, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Irwin, a borough in Westmoreland County, Pennsylvania.
Today
86°F
Patchy Fog then Sunny
Patchy fog before 9am. Sunny, with a high near 86. East wind around 3 mph.
7-day forecast for Irwin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 86°F | Patchy Fog then Sunny | 3 mph E | 0% |
| Tonight | 67°F | Partly Cloudy | 2 to 6 mph SE | 1% |
| Wednesday | 87°F | Partly Sunny then Isolated Showers And Thunderstorms | 2 to 6 mph SE | 20% |
| Wednesday Night | 68°F | Scattered Showers And Thunderstorms | 6 mph S | 48% |
| Thursday | 86°F | Showers And Thunderstorms | 5 to 9 mph SW | 75% |
| Thursday Night | 68°F | Showers And Thunderstorms | 3 to 8 mph SW | 75% |
| Friday | 85°F | Showers And Thunderstorms | 5 to 9 mph SW | 82% |
| Friday Night | 67°F | Showers And Thunderstorms | 7 mph SW | 82% |
| Saturday | 84°F | Showers And Thunderstorms Likely | 6 to 9 mph SW | 57% |
| Saturday Night | 67°F | Showers And Thunderstorms Likely | 5 to 8 mph SW | 57% |
| Sunday | 86°F | Slight Chance Showers And Thunderstorms | 6 to 12 mph SW | 24% |
| Sunday Night | 69°F | Slight Chance Showers And Thunderstorms | 9 mph SW | 24% |
| Monday | 87°F | Chance Showers And Thunderstorms | 9 to 14 mph SW | 40% |
| Monday Night | 68°F | Chance Showers And Thunderstorms | 7 to 12 mph SW | 50% |
Forecast source: National Weather Service (api.weather.gov) for Irwin (40.325, -79.700). Updated through the day.
Growing snapshot for Irwin
Last spring frost
Apr 22
First fall frost
Oct 25
Growing season
186 days
Hardiness zone
6b
More local growing data for Irwin: nearby ZIP 15692 weather · frost dates · planting calendar · Pennsylvania frost dates
Nearby towns & communities
Adamsburg
Arona
Avonmore
Bear Rocks
Bradenville
Calumet
Charleroi
Collinsburg
Crabtree
Delmont
Derry
Donegal
East Vandergrift
Export
Fellsburg
Grapeville
Greensburg
Harrison City
Herminie
Hostetter
Hunker
Hyde Park
Industry
Jeannette
Kiskimere
Latrobe
Laurel Mountain
Lawson Heights
Leechburg
Level Green
Climate data from the nearest NOAA station, Murrysville 2 Sw, Pa (6.1 mi from Irwin). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.