Western Washington Temperatures Dropped to Seasonal Lows

The region recorded chilly morning lows on October 12 before a shift toward warmer conditions.

Updated on Oct. 13, 2026 in Current Conditions

Frost-covered evergreen needles and wild grasses in a meadow under low, clear morning light in the Pacific Northwest. — Western Washington recorded seasonal low temperatures on October 12, 2026, driven by clear skies and radiational cooling across the region. AI Illustration. Upload story photo >

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Western Washington experienced a sharp temperature drop on the morning of October 12, 2026. Residents in Shelton recorded 27 degrees, while Boeing Field in Seattle reached 37 degrees.

Why it matters

Radiational cooling during clear and calm nights drove these low temperatures as fall progresses. Decreasing daylight hours further limit the opportunity for significant daytime warming.

Meteorologists recorded a morning low of 27 degrees in Shelton and 37 degrees at Boeing Field on October 12. Daylight in Seattle reached 11 hours, a duration currently decreasing by more than three minutes each day.

The details

The drop was caused by radiational cooling, which occurs when clear skies allow the Earth's surface to lose heat to space overnight. In contrast, cloud cover typically acts as a blanket to trap heat near the surface and prevent such sharp temperature fluctuations.

October 12, 2026: Morning low temperatures were recorded in Seattle and Shelton.
October 13, 2026: Daylight duration across the region dipped below 11 hours.
October 15-16, 2026: Temperatures are expected to reach the upper 60s and 70s.
December 21, 2026: Daylight will reach an annual minimum of 8 hours and 25 minutes.

Seasonal Patterns

These temperature swings reflect the transition into late fall, aligning with the predictable decline in daylight duration tracked by the National Weather Service. The current shift toward shorter days and colder nights follows the established cycle that will reach its solar nadir in December.

Residents should prepare for a significant temperature swing as daytime highs approach 70 degrees by mid-week. Ensure outdoor plants are protected from lingering cold-morning temperatures and adjust heating systems for the fluctuating conditions.

The takeaway

As daylight continues to decrease by three minutes daily, the region will face increasingly limited daytime warming. Homeowners should expect these sharp transitions between cold mornings and warmer afternoons to persist through the transition into late autumn.