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Irwin, PA Weather Tomorrow

Access tomorrow's Irwin weather forecast and the next 5 days of weather details, including precipitation probability, daily and nightly weather conditions, high and low temperature trends, sunrise and sunset information, sky cover, wind speed, wind direction, and wind chill for the Irwin area and around Westmoreland county, Pennsylvania.
Updated: Fri Sep 4th 2026 12:00 AM EDT
Irwin, PA Weather – 9-4 – Scattered Showers
80° / 67°
Scattered Showers
On and off showers are set to occur in Irwin, with a high of 80°F and a low of 67°F. The chance of rain is 87% with an estimated 0.68in. Winds will be light at 9mph and gusts of 16.8mph at 6 PM. High humidity with average of 87% is anticipated, the maximum being 98% at 6 AM and 66% being its lowest at 1 PM. Barometric pressure is its highest of 30.02inHg at 11 AM, a lowest point of 29.91inHg at 5 PM with an avg 29.97inHg.
Irwin, PA Weather – 9-5 – Scattered Showers
73° / 67°

Weather Tomorrow

Scattered Showers
Irwin may see passing showers, with daytime highs of 73°F and overnight lows near 67°F. The chance of rain is 91% with an estimated 0.35in. Winds will be light at 9mph and gusts of 20mph at 12 PM. High humidity with average of 94% is anticipated, the maximum being 98% at 6 AM and 85% being its lowest at 3 PM. Barometric pressure is its highest of 29.93inHg at 1 AM, a lowest point of 29.82inHg at 7 PM with an avg 29.88inHg.
Irwin, PA Weather – 9-6 – Sunny
76° / 60°
Sunny
Highs will reach 76°F with lows near 60°F in Irwin, where sunshine is. There might be light rainfall having a 19% chance with an estimated 0in. Winds will be light at 10mph and gusts of 16.8mph at 9 AM. High humidity with average of 81% is anticipated, the maximum being 97% at 3 AM and 53% being its lowest at 4 PM. Barometric pressure is its highest of 30.06inHg at 11 PM, a lowest point of 29.87inHg at 3 AM with an avg 29.95inHg.
Irwin, PA Weather – 9-7 – Sunny
75° / 56°
Sunny
In Irwin, sunshine is likely with a high near 75°F and a low around 56°F. There's a very small chance of rainfall, only about 8%. Winds will be light at 7mph and gusts of 15.4mph at 6 AM. The humidity will be on the higher side, averaging about 72%, the maximum being 89% at 1 AM and 48% being its lowest at 4 PM. Barometric pressure is its highest of 30.18inHg at 9 AM, a lowest point of 30.08inHg at 12 AM with an avg 30.14inHg.
Irwin, PA Weather – 9-8 – Overcast
75° / 57°
Overcast
Skies will be overcast in Irwin, with a high of 75°F and a low of 57°F. There might be light rainfall having a 18% chance. Winds will be light at 6mph and gusts of 15.9mph at 12 AM. The humidity will be on the higher side, averaging about 72%, the maximum being 88% at 7 AM and 53% being its lowest at 5 PM. Barometric pressure is its highest of 30.22inHg at 8 AM, a lowest point of 30.16inHg at 3 AM with an avg 30.19inHg.
Irwin, PA Weather – 9-9 – Overcast
84° / 65°
Overcast
Cloud-filled skies are in the forecast for Irwin, with a high of 84°F and a low of 65°F. There's a moderate 40% chance of rainfall with an estimated 0.02in. Wind will be moderate, blowing around 13mph on average and gusts of 30.7mph at 11 PM. The humidity will be on the higher side, averaging about 71%, the maximum being 92% at 11 PM and 55% being its lowest at 2 PM. Barometric pressure is its highest of 30.17inHg at 1 AM, a lowest point of 29.99inHg at 8 PM with an avg 30.1inHg.

Currently

Patchy Rain Nearby 71°F
29.98 inHg.
Barometer
89%
Humidity
S 5 mph
Wind
Patchy Rain Nearby

5 Day Forecast Nearby

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