The automated updater targets NOAA/NCEI 1991–2020 Monthly Climate Normals using the NCEI Access Data Service. NOAA describes U.S. Climate Normals as official 30-year averages and statistics for temperature, precipitation and other variables.
The updater retrieves the latest available monthly residential electricity price by state from the U.S. Energy Information Administration retail-sales API.
The 0–100 score is a proprietary comparative index. It weights January normal minimum temperature (48%), number of months with normal minimum temperature below freezing (22%), annual precipitation exposure (10%) and residential electricity price (20%). It is not a forecast of sauna performance.
City comparisons use a 9 kW electric heater, climate-adjusted warm-up full-load-equivalent hours and a 60% full-load-equivalent assumption during a one-hour session. These assumptions create consistent comparisons; they are not a promise of actual consumption.
The GitHub workflow runs weekly. EIA rates can change as new monthly data are published. NOAA climate normals are intentionally long-term baselines; the updater also stores recent observation context when the matching station returns usable daily data.
This site does not replace manufacturer sizing, structural design, electrical engineering, permitting or local building requirements. City-level values use nearby climate stations and state-level electricity rates rather than a specific property or utility tariff.
NOAA U.S. Climate Normals →
NCEI Access Data Service →
EIA retail electricity data →