December Windstorms Lead Washington's Storm Year
By StormAuditor Editorial Team · Published 2026-09-23 · Updated 2026-09-24
Based on public NOAA and National Weather Service records, published under StormAuditor's methodology and data-source standards. Radar-derived hail sizes are estimates unless attributed to a ground report.
Damage-threshold ranges in this article are general guidance synthesized from industry and federal research — IBHS building-performance research, NWS severe criteria, and product standards such as UL 2218 (hail impact resistance) and ASTM D3161/D7158 (shingle wind ratings). Actual performance depends on product rating, age, installation quality, exposure, and impact characteristics — thresholds describe when damage becomes possible, not when it occurs.
Washington logged 1,330 storm events across all 39 counties in the 12 months through August 25, 2026, and December owned the biggest days — including estimated gusts to 100 mph and 221 events on December 17, 2025.
Washington's strongest wind day in the 12 months through August 25, 2026 arrived on December 17, 2025. StormAuditor's record for that date estimates peak gusts near 100 mph. The same day produced 221 separate flood, hail, and wind events statewide. No other date in the 12 months through August 25, 2026 came close to that count.
December: Washington's windstorm month
December did not deliver one storm. It delivered a train of them. Estimated gusts reached 93 mph on December 8, 2025. The next day, December 9, added 77 flood and wind events. December 10 matched the 93 mph mark and logged 126 events of its own. A week later, the December 17 storm topped the year on both gust strength and event count.
That rhythm fits Washington's climate. Pacific storm systems tend to line up in early winter and land back to back. When they do, wind claims cluster into a narrow window of dates. An adjuster or homeowner researching a December date of loss often has several candidate storms within days of each other. Precise dates matter here more than in most states.
March offered a smaller echo of the same pattern. Estimated gusts hit 94 mph on March 11, 2026, with 62 flood and wind events. March 12 followed at 91 mph and 67 events. Two-day sequences like this are a recurring Washington signature.
The year in numbers
Across the 12 months through August 25, 2026, StormAuditor's database holds 1,330 storm events for Washington. Activity touched all 39 counties. Wind led by a wide margin with 973 events. Flood followed at 341. Hail accounted for 114, and a single tornado event rounds out the list.
Hail was a smaller part of Washington's year. The largest ground hail report in the 12 months through August 25, 2026 was 1.75 inches near Odessa on May 28, 2026, a day radar estimated hail to 1.78 inches. Radar also flagged larger hail estimates on January 11 and April 27, 2026, but no ground hail reports were logged on either date, and radar hail values without ground support, especially in winter, deserve caution. That May 28 storm also generated 137 flood, hail, and wind events, the busiest day outside winter.
County patterns split along the Cascades. Chelan, Benton, and Yakima each logged 84 events over the year. Benton stands out for intensity. There, 63 events carried StormAuditor's high or severe event rating. Spokane recorded 80 events and Whitman 61. On the west side, King County logged 73 events and Grays Harbor 48. Kittitas, straddling the mountains, added 56.
How StormAuditor estimates it
StormAuditor's SAWE-2 wind engine and SAHE-2 hail engine blend radar, station observations, and official reports. The output is an address-level estimate of the public weather record. Every value on this page is an estimate, not a certainty, and never a promise about any insurance outcome. The full modeling approach lives at wind methodology and hail methodology.
Practical steps after a Washington windstorm
Start with the date. December's stacked storms make date confusion the most common research error in this state. Use date-of-loss weather research to line up the candidate storm days near your loss date, then compare them.
Next, look at your specific location. Statewide peaks like 100 mph rarely reflect conditions at a single address. An address lookup shows the estimated values where the property actually sits.
For claims work, a documented wind report gives adjusters and contractors a common reference point. StormAuditor screens wind at 45 mph and hail at 0.75 inch. These screening thresholds sit below the NWS severe criteria of 58 mph gusts and 1.00 inch hail. A screening-level hit is a reason to inspect, not a conclusion about damage.
Notable storm days
- December 8, 2025 — statewide — estimated gusts to 93 mph, wind
- December 10, 2025 — statewide — estimated gusts to 93 mph; 126 flood and wind events
- December 17, 2025 — statewide — estimated gusts to 100 mph; 221 flood, hail, and wind events
- March 11, 2026 — statewide — estimated gusts to 94 mph; 62 flood and wind events
- March 12, 2026 — statewide — estimated gusts to 91 mph; 67 flood and wind events
- May 28, 2026 — statewide — radar-estimated hail to 1.78 inches; 137 flood, hail, and wind events
Limitations
These figures are estimates of the public weather record, drawn from radar, models, and reporting networks. Peak gust values reflect the strongest estimated point in the state, not typical conditions at any one address. Radar-estimated hail sizes can differ from what fell on the ground, especially in Washington's complex terrain. Local effects — gaps, ridgelines, and the Cascade rain shadow — can push real conditions above or below the estimate. Read the full limitations page before relying on any single number.
FAQ
When was the big Washington windstorm in December 2025?
The strongest day was December 17, 2025, with estimated gusts to 100 mph and 221 storm events statewide. Earlier storms on December 8 and December 10 each brought estimated gusts to 93 mph.
Did King County have storm activity from August 2025 to August 2026?
Yes. King County logged 73 storm events over the 12 months through August 25, 2026, and 49 of them carried StormAuditor's high or severe event rating.
How large was the biggest hail in Washington from August 2025 to August 2026?
The largest ground hail report in the 12 months through August 25, 2026 was 1.75 inches near Odessa on May 28, 2026. Larger radar estimates on January 11 and April 27, 2026 had no ground hail reports that day.
What wind speed counts as severe in Washington?
The NWS defines severe wind as gusts of 58 mph or higher. StormAuditor applies a lower 45 mph screening threshold to flag dates worth a closer look.
How do I check what happened at my address on a specific date?
Run an address lookup for the property. A free report snapshot also shows whether screening-level wind or hail is estimated near your date of loss.