Data sources & attribution

• Source data — numbers published by a weather provider or model, shown as received (converted to consistent units).
• Official warnings — watches, warnings, and advisories issued by a government meteorological agency. WeatherSignal republishes them with the issuing agency, area, effective time, and expiration. WeatherSignal never generates a government alert.
• WeatherSignal calculations — scores, windows, and checks computed by us from source data using fixed published thresholds, documented on the methodology page.
• WeatherSignal summaries — plain-language sentences assembled from the same source values by fixed rules, not by an AI model.

• NOAA / National Weather Service (api.weather.gov)

  Information:

  Official watches, warnings, advisories, and statements; US forecast products.

  Coverage:

  United States and territories

  Freshness:

  Alerts polled every few minutes; expiration times come from the issuing office.

  Attribution:

  US Government work, public domain. Alerts are shown with the issuing agency named.

  Official provider site

• Open-Meteo

  Information:

  Primary global forecast model data: temperature, feels-like, precipitation, wind, humidity, dew point, UV, cloud cover, sunrise/sunset.

  Coverage:

  Worldwide

  Freshness:

  Model runs update hourly; WeatherSignal caches responses for minutes, not hours.

  Attribution:

  Open-Meteo, CC BY 4.0.

  Official provider site

• MET Norway Locationforecast

  Information:

  Backup global forecast source used automatically when the primary provider is rate-limited or unavailable.

  Coverage:

  Worldwide

  Freshness:

  Updated by MET Norway on their published schedule; the source time is shown on the panel.

  Attribution:

  Norwegian Meteorological Institute, NLOD / CC BY 4.0.

  Official provider site

• Open-Meteo Air Quality

  Information:

  AQI, PM2.5, PM10, ozone, NO₂, SO₂, CO, and dust, with the published category guidance for the scale in use.

  Coverage:

  Worldwide (US AQI and European AQI scales)

  Freshness:

  Hourly.

  Attribution:

  Open-Meteo, CC BY 4.0, based on CAMS model data.

  Official provider site

• RainViewer

  Information:

  Radar and precipitation nowcast tiles used for the radar view.

  Coverage:

  Worldwide radar composite where available

  Freshness:

  Tiles typically refresh every 10 minutes.

  Attribution:

  RainViewer, credited on the radar page.

  Official provider site

• NOAA National Hurricane Center

  Information:

  Tropical cyclone products referenced from the radar and alerts views.

  Coverage:

  Atlantic and Eastern Pacific basins

  Freshness:

  Per NHC advisory schedule.

  Attribution:

  US Government work, public domain.

  Official provider site

• Open-Meteo Geocoding

  Information:

  Turns a typed city, place, or ZIP into coordinates, country, and time zone.

  Coverage:

  Worldwide

  Freshness:

  Static gazetteer, refreshed by the provider.

  Attribution:

  Open-Meteo, CC BY 4.0.

  Official provider site

• BigDataCloud reverse geocoding

  Information:

  Turns detected coordinates into a readable place name. If it fails, the forecast still loads from the coordinates.

  Coverage:

  Worldwide

  Freshness:

  On demand.

  Attribution:

  BigDataCloud.

  Official provider site

• ipwho.is

  Information:

  Optional approximate, city-level location lookup used only when you press “Use my location” and the browser cannot provide coordinates.

  Coverage:

  Worldwide

  Freshness:

  On demand.

  Attribution:

  ipwho.is.

  Official provider site

• Provider status pages (Statuspage-format feeds)

  Information:

  Official incident feeds published by Cloudflare, GitHub, Stripe, OpenAI, Discord, Shopify, DigitalOcean, Vercel, npm, Twilio, Reddit, and Atlassian.

  Coverage:

  Per provider, global

  Freshness:

  Polled every few minutes; each card links to the provider's own status page.

  Attribution:

  Each provider's own status feed, linked and named on the page.

  Official provider site

• Public reachability probes

  Information:

  WeatherSignal measures response time and availability of public DNS resolvers, CDN edges, and cloud object-storage endpoints to compute Internet Health.

  Coverage:

  Global public endpoints

  Freshness:

  Measured on request, cached briefly.

  Attribution:

  WeatherSignal measurement, not a provider statement.

  Official provider site

Every panel shows the time the source published its data and the time WeatherSignal last checked. When a value passes its staleness window, WeatherSignal labels it as delayed rather than presenting it as current. If a provider is unavailable, the panel says so instead of showing an older number silently.