Data & coverage

Forge provides global weather and location data, built on a worldwide grid model combined with a curated gazetteer for name-based lookup. This page explains how coverage works so you can set expectations for accuracy and freshness.

Global grid model

Weather data is generated from a global atmospheric grid model that is interpolated to the exact lat/lon you request. This means:

Any valid coordinate pair on Earth (lat between -90 and 90, lon between -180 and 180) returns a result — there are no "gaps" in ocean or remote areas.
Accuracy is generally highest in areas with dense observation-station coverage (North America, Europe, East Asia) and somewhat lower in sparsely instrumented regions (open ocean, polar regions, parts of the Sahara and central Asia), where the model leans more heavily on satellite and reanalysis data.
Requesting by city resolves the name to a representative coordinate for that place (typically a city center or administrative centroid) before running the same grid lookup — so city=london and the equivalent lat/lon pair for central London return effectively the same data.

City gazetteer

Name-based lookups (city on /v1/weather, and q on /v1/geocode) are resolved against a curated gazetteer of 60+ major world cities, covering national and regional capitals plus other high-population hubs, including:

London, Paris, Berlin, Madrid, Rome, Amsterdam, Dublin, Lisbon, Vienna, Zurich, Stockholm, Oslo, Copenhagen, Helsinki, Warsaw, Prague, Budapest, Athens, Istanbul, Moscow, New York, Los Angeles, Chicago, Toronto, Vancouver, Mexico City, São Paulo, Rio de Janeiro, Buenos Aires, Bogotá, Lima, Santiago, Tokyo, Osaka, Seoul, Beijing, Shanghai, Hong Kong, Singapore, Bangkok, Jakarta, Manila, Mumbai, Delhi, Bengaluru, Karachi, Dhaka, Dubai, Riyadh, Tel Aviv, Cairo, Lagos, Nairobi, Johannesburg, Cape Town, Casablanca, Sydney, Melbourne, Auckland, Wellington, and Honolulu.

If a name isn't in the gazetteer, /v1/weather?city=... returns 404 not_found; use /v1/geocode with a broader query, or fall back to explicit lat/lon coordinates, which always resolve.

Update cadence

Current conditions refresh continuously; expect current.observed_at to be within the last 10–15 minutes for well-instrumented regions.
Forecast data (forecast.daily) is recomputed several times daily as new model runs complete.
Gazetteer entries (city names, populations, timezones) are reviewed quarterly; population figures reflect the most recent official or UN estimate available at review time.

Units quirk

When units=imperial is requested, only temp, feels_like, and dew_point convert to Fahrenheit, and wind_speed converts to mph. precip_mm and visibility_km remain in their metric units regardless of the units parameter — this is a documented quirk, not a bug, so don't assume every field flips units together. The legacy temp_c field is always Celsius no matter what units you request, which makes it useful as a stable reference value if you're storing historical data across unit settings.

Next steps

See the weather reference for the complete field list, including the units quirk in context.
See the geocode reference for resolving free-text place names to coordinates.