Upload an EPW weather file and read the whole climate on one page — monthly temperatures with ASHRAE-style design percentiles, sun-path arcs, a wind rose, measured monthly radiation, and all 8,760 hours scattered on a psychrometric chart with Givoni-style strategy shares. The same parity-tested parser Eco-Architect, Assayer and Daylighter use. Parsed in your browser — nothing is uploaded. Client-side.
Parsed in your browser — nothing is uploaded. Free typical-year EPWs for most of the world: climate.onebuilding.org.
Sources & methods
Parser. Your .epw is read entirely in your browser by the toolkit’s shared EPW parser (gable-studio/web/v2/weather.js — the same module behind Eco-Architect V4/V5, Assayer and Daylighter). Nothing is uploaded or stored.
EPW columns read (0-indexed, missing-value sentinels skipped, never faked): 6 dry-bulb °C · 7 dew point °C · 8 relative humidity % · 9 station pressure Pa · 13/14/15 global / direct-normal / diffuse-horizontal irradiance Wh/m² · 20/21 wind direction ° and speed m/s · 22 total sky cover. Not parsed — and therefore not shown, rather than faked: precipitation, snow depth, and the illuminance columns.
Temperature & design values. Monthly ribbon = mean/min/max of the hourly dry-bulb per month (RH strip likewise). Design values are rank percentiles of all dry-bulb hours: heating 99.6% (coldest 0.4% excluded), cooling 0.4% — the ASHRAE convention, computed from this file, not looked up from the ASHRAE tables. The “monthly swing” is each month’s max−min averaged over the year — an upper bound on the daily diurnal swing.
Sun path. Solar GEOMETRY from the NOAA position algorithm (Surveyor’s ported engine) at the file header’s lat/lon/timezone — solstices + equinox arcs. It uses no measured EPW columns; the measured sky is the radiation card.
Wind rose. 16 compass sectors; hours below 0.5 m/s counted as calm. The parser bins speeds at 0.5/2/4/6/8/10 m/s (7 bins); the chart draws 5 bands (<2, 2–4, 4–6, 6–8, 8+ m/s), so adjacent bins are merged — no hour dropped. Prevailing direction is the speed-weighted vector mean of the “from” bearing.
Radiation. Monthly GHI/DNI/DHI totals are straight sums of the hourly Wh/m² columns ÷ 1000 — measured (typical-year) data, no sky model applied.
Psychrometrics & comfort. The hour-cloud computes humidity ratio w = 0.622·pv/(P − pv) with saturation pressure from the Arden Buck (1981) equation and the file’s mean station pressure. The strategy shares are core.js’s climateFingerprint: each hour binned into the cheapest passive strategy that can hold comfort (Givoni 1969 / Milne & Givoni 1979-style zones — approximate, tunable teaching boundaries, not validated polygons), identical to Eco-Architect’s comfort fingerprint. Buck and core.js’s Magnus fit agree to under 1% across the building-climate range.
Data source. Free typical-meteorological-year EPWs: climate.onebuilding.org. A TMY is a stitched “typical” year of measured months — good for reading a climate, not a record of any single real year.