Mild climate load. Physical climate score and electricity cost are reported separately.
Seattle has a mild climate load. Its Climate Stress Score of 15.5 is below the indexed-metro median of 37.9. The January normal low is 36.8°F, and 0 months have a normal low below freezing.
The primary planning issue in this profile is site design and equipment selection rather than severe climate. The standardized 9 kW session estimate is $2.14, below the indexed-metro median of $2.46; this uses the Washington statewide residential electricity average, not a city utility quote. The selected snowfall record reports 3.8 inches annually.
For construction or maintenance work that is easier in moderate conditions, the monthly normals point to March, April, May, June. This is a climate-screening observation, not a construction schedule or permit recommendation.
| Profile | Climate | 9 kW session | Jan. low |
|---|---|---|---|
| Seattle | 15.5 | $2.14 | 36.8°F |
| Indexed median | 37.9 | $2.46 | — |
| Closest index peer: Portland | 16.3 | $2.32 | 37.3°F |
Climate source: NOAA/NCEI U.S. Monthly Climate Normals 1991–2020 (direct by-station archive)
Temperature/precipitation station: USW00024234 — SEATTLE BOEING FLD (4.5 mi from city reference point)
Snow station: USW00094290 — SEATTLE SAND PT WFO (6.4 mi from city reference point)
Normal period: 1991–2020
Electricity source: EIA residential retail electricity price (2026-07)
Rate geography: Washington statewide residential average
Dataset generated: September 28, 2026
Recent observations through: September 22, 2026
Snowfall status: available. Missing values are not included in rankings.
