Irwin, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Irwin, a borough in Westmoreland County, Pennsylvania.
Today
76°F
Partly Sunny
Partly sunny, with a high near 76. South wind 5 to 9 mph.
7-day forecast for Irwin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 76°F | Partly Sunny | 5 to 9 mph S | 14% |
| Tonight | 60°F | Light Rain | 12 mph S | 95% |
| Thursday | 70°F | Light Rain Likely then Mostly Sunny | 9 to 15 mph SW | 58% |
| Thursday Night | 47°F | Partly Cloudy | 2 to 7 mph SW | 1% |
| Friday | 64°F | Partly Sunny then Slight Chance Light Rain | 3 to 9 mph SW | 20% |
| Friday Night | 41°F | Chance Light Rain | 5 to 9 mph W | 35% |
| Saturday | 53°F | Chance Light Rain | 9 to 15 mph W | 33% |
| Saturday Night | 35°F | Chance Light Rain | 7 to 13 mph W | 25% |
| Sunday | 55°F | Partly Sunny | 8 to 17 mph W | 8% |
| Sunday Night | 32°F | Partly Cloudy | 9 to 13 mph SW | 6% |
| Monday | 56°F | Mostly Sunny | 9 to 16 mph W | 11% |
| Monday Night | 33°F | Partly Cloudy | 8 to 13 mph SW | 11% |
| Tuesday | 60°F | Mostly Sunny | 13 to 20 mph SW | 4% |
| Tuesday Night | 33°F | Partly Cloudy | 5 to 12 mph W | 4% |
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 Nov 4, 2026.