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Union, WA Weather Tomorrow

Know what to expect with tomorrow's Union weather and the next 5 days of forecasts covering 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 Union area and around Mason county, Washington.
Updated: Tue Sep 29th 2026 5:00 AM PDT
Union, WA Weather – 9-29 – Light Rain
53° / 48°
Light Rain
In Union, periods of rain are likely with highs near 53°F and lows around 48°F. The chance of rain is 94% with an estimated 1.17in. Winds will be light at 5mph and gusts of 6.7mph at 6 AM. High humidity with average of 99% is anticipated, the maximum being 100% at 6 AM and 96% being its lowest at 11 PM. Barometric pressure is its highest of 30.01inHg at 11 PM, a lowest point of 29.87inHg at 7 AM with an avg 29.91inHg.
Union, WA Weather – 9-30 – Overcast
59° / 45°

Weather Tomorrow

Overcast
In Union, cloud-filled skies are likely with a high near 59°F and a low around 45°F. There's a moderate 32% chance of rainfall with an estimated 0in. Winds will be light at 5mph and gusts of 15.4mph at 5 PM. The humidity will be on the higher side, averaging about 80%, the maximum being 99% at 3 AM and 52% being its lowest at 3 PM. Barometric pressure is its highest of 30.15inHg at 8 AM, a lowest point of 30.02inHg at 12 AM with an avg 30.09inHg.
Union, WA Weather – 10-1 – Overcast
63° / 50°
Overcast
Daytime highs will reach 63°F with lows dropping to 50°F in Union, where it will be overcast. There might be light rainfall having a 15% chance. Winds will be light at 5mph and gusts of 15mph at 9 PM. The humidity will be on the higher side, averaging about 68%, the maximum being 91% at 11 PM and 47% being its lowest at 12 PM. Barometric pressure is its highest of 30.06inHg at 12 AM, a lowest point of 29.95inHg at 4 PM with an avg 30inHg.
Union, WA Weather – 10-2 – Scattered Showers
60° / 51°
Scattered Showers
Union could see scattered showers with daytime highs of 60°F and nighttime lows near 51°F. There's a moderate 38% chance of rainfall with an estimated 0.01in. Winds will be light at 5mph and gusts of 16.1mph at 12 AM. High humidity with average of 86% is anticipated, the maximum being 97% at 6 AM and 70% being its lowest at 12 PM. Barometric pressure is its highest of 30.13inHg at 11 PM, a lowest point of 29.98inHg at 1 AM with an avg 30.05inHg.
Union, WA Weather – 10-3 – Sunny
68° / 50°
Sunny
Union is set for sunshine with temperatures peaking at 68°F and dipping to 50°F. There's a very small chance of rainfall, only about 6%. Winds will be light at 6mph and gusts of 15.9mph at 8 PM. The humidity will be on the higher side, averaging about 66%, the maximum being 91% at 12 AM and 43% being its lowest at 2 PM. Barometric pressure is its highest of 30.13inHg at 1 AM, a lowest point of 29.98inHg at 5 PM with an avg 30.06inHg.
Union, WA Weather – 10-4 – Sunny
70° / 55°
Sunny
In Union, bright and sunny conditions with highs near 70°F and lows around 55°F. There's a very small chance of rainfall, only about 5%. Winds will be light at 5mph and gusts of 15.7mph at 2 PM. Humidity levels should be comfortable, sitting around 57% on average, the maximum being 80% at 10 PM and 43% being its lowest at 11 AM. Barometric pressure is its highest of 29.98inHg at 12 AM, a lowest point of 29.89inHg at 5 PM with an avg 29.93inHg.

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