SnowWatt

Snow zone — WA-west · OR-west

Heated driveways and snow-melting mats in the Pacific Northwest Valleys (Puget Sound, Willamette, lower Columbia)

Snowfall normals, electricity rates and melt-capability figures for the Pacific Northwest Valleys (Puget Sound, Willamette, lower Columbia), computed from NOAA and EIA data.

This page is data only — the written analysis has not been through editorial review yet, so it is marked noindex until it has.

Climate normals

Annual snowfall
6.8 in
Snow days ≥ 1 in
2.2
Season length
22 wk
Electricity
14.24¢

6.8 in a year at Seattle-Tacoma AP, WA — NOAA GHCN-Daily, 1991-2020 normals. Electricity: Unweighted mean of the January 2026 EIA residential price for WA, OR.

Will a mat keep up here?

Melt capability against this zone's snowfall

Melt gauge — HeatTrak HR20-60 in Pacific Northwest Valleys (Puget Sound, Willamette, lower Columbia)

  1. ≥ 0.1 in4.6 d/yr3 min
  2. ≥ 1 in2.2 d/yr30 min
  3. ≥ 3 in0.7 d/yr1.5 h
  4. ≥ 5 in0.3 d/yr2.5 h
  5. ≥ 10 in0.0 d/yr5.0 h
Design day
1 in
Clears in
30 min
Running per year
3.4 h
Melt rate (claimed)
2 in/hr
Keeps up

A 1 in day clears in 30 min, on about 3.4 h of running a year.

  • The melt rate is the manufacturer's claim, not a measurement. SnowWatt has not operated this product. Every portable mat on the market quotes the same 2 in/hr, which makes it a marketing constant rather than a differentiator.
  • Clear time assumes continuous running on a mat that starts clear. It is the time to melt that much accumulation, not a storm-duration model, and it does not account for drifting, refreeze, or snow arriving while the mat works.
  • The design day is a 30-year normal, not a forecast. 6.8 in a year at Seattle-Tacoma AP, WA (NOAA GHCN-Daily, 1991-2020), the largest daily threshold crossed at least once a year. Your worst day will be worse.

What it costs to run

Running cost — Pacific Northwest Valleys (Puget Sound, Willamette, lower Columbia)

Power draw
300 VA
Per design-day storm
$0.02
Per normal season
$0.15
Electricity
14.24¢
  • HeatTrak does not publish a wattage for this product. The figure above is SnowWatt's own arithmetic — 120 V × 2.5 A — and it is apparent power in VA, not a measured wattage. HeatTrak states no tolerance on this figure, which is not the same as a tolerance of zero — treat the cost below as an order of magnitude, not a quote. Treat it as an upper bound on real power, and see the methodology page for why we will not print it as watts.
  • Hours come from the melt gauge above: 30 min to clear the design-day accumulation, and about 3.4 h a year to keep pace with normal snowfall. Both assume continuous running and no idling, standby or preheat — so the season figure is a floor, not a forecast.
  • Electricity at 14.24¢/kWh (USD). Unweighted mean of the January 2026 EIA residential price for WA, OR.

The same figures for an embedded system, which publishes a real wattage and so can be costed exactly:

Running cost — Pacific Northwest Valleys (Puget Sound, Willamette, lower Columbia)

Power draw
1500 W
Per design-day storm
—
Per normal season
—
Electricity
14.24¢
  • Power draw is the manufacturer's published rating of 1500 W.
  • Electricity at 14.24¢/kWh (USD). Unweighted mean of the January 2026 EIA residential price for WA, OR.

Sources

Lowest-snowfall zone on the site and the clearest "do not heat your driveway" answer: under 7 in a year at Sea-Tac and about two days a year over an inch. The buying question here is a doormat or a stair tread, not a system. Wet heavy snow near freezing is the local hazard, but heavyWetSnowShare has no published source — see VERIFY-TODO.

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