Irwin, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Irwin, a borough in Westmoreland County, Pennsylvania.
Today
78°F
Partly Sunny
Partly sunny, with a high near 78. Southeast wind around 5 mph.
7-day forecast for Irwin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 78°F | Partly Sunny | 5 mph SE | 3% |
| Tonight | 64°F | Chance Rain Showers | 8 mph SE | 45% |
| Sunday | 77°F | Showers And Thunderstorms | 8 to 12 mph SW | 97% |
| Sunday Night | 55°F | Showers And Thunderstorms | 12 mph N | 92% |
| Monday | 68°F | Chance Rain Showers | 13 mph NE | 40% |
| Monday Night | 53°F | Showers And Thunderstorms Likely | 14 mph E | 68% |
| Tuesday | 63°F | Showers And Thunderstorms Likely | 14 to 18 mph E | 68% |
| Tuesday Night | 50°F | Rain Showers Likely | 15 to 18 mph E | 62% |
| Wednesday | 61°F | Rain Showers Likely | 17 mph E | 62% |
| Wednesday Night | 50°F | Showers And Thunderstorms Likely | 10 to 16 mph E | 56% |
| Thursday | 66°F | Chance Rain Showers | 13 mph E | 54% |
| Thursday Night | 49°F | Chance Showers And Thunderstorms | 6 to 13 mph NE | 30% |
| Friday | 68°F | Partly Sunny then Slight Chance Rain Showers | 6 to 10 mph NE | 19% |
| Friday Night | 49°F | Slight Chance Rain Showers then Partly Cloudy | 6 to 10 mph NE | 19% |
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
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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 Sep 19, 2026.