Where Aviation Weather Actually Comes From (and Which Sources Count)
There is no global weather service. There is a treaty, a set of formats, and about a hundred and ninety national meteorological services that agree to produce the same products in the same code so that a report from Jakarta reads the same way as a report from Reykjavík.
That structure explains something that confuses people who arrive from consumer weather apps: why the authoritative source changes depending on where you are flying, and why an app that shows you a METAR is not the same thing as a briefing.
Who issues what#
Under the ICAO framework, each state designates a meteorological authority responsible for aviation weather in its airspace. That authority runs the observations at its aerodromes, issues the TAFs, and operates the watch office that puts out SIGMETs. Two further layers sit above it: World Area Forecast Centres produce the global upper-wind and significant-weather data used for route planning, and Volcanic Ash Advisory Centres cover ash for defined regions.
| Layer | Who | What they issue |
|---|---|---|
| Aerodrome | Designated national service | METAR, SPECI, TAF, aerodrome warnings |
| Airspace | Meteorological watch office | SIGMET, AIRMET, volcanic ash and tropical cyclone SIGMETs |
| Global | World Area Forecast Centres (London, Washington) | Upper wind and temperature, significant weather charts |
| Volcanic | Nine Volcanic Ash Advisory Centres | Ash advisories and forecast ash cloud positions |
| Tropical | Tropical Cyclone Advisory Centres | Cyclone position and forecast track for aviation |
This is why our region pages link a different service for each part of the world. There is no single authoritative site, by design.
The services you will actually meet#
- United States — the NOAA Aviation Weather Center publishes METAR, TAF, SIGMET and graphical products free and without registration.
- Canada — NAV CANADA operates the aviation weather and flight planning service.
- United Kingdom — the Met Office provides aviation services, including the London VAAC for volcanic ash.
- Germany — DWD runs a pilot briefing service covering central Europe.
- India — the India Meteorological Department issues the reports; AAI publishes the aeronautical information.
- Brazil — REDEMET, operated by the air force, is the aviation weather portal.
- Japan — the Japan Meteorological Agency, including the Tokyo VAAC.
- Australia and New Zealand — the Bureau of Meteorology and MetService respectively.
Availability differs sharply. Some services publish everything openly on the web; others require a registered account tied to a licence, and a few make raw data available only through a national briefing system.
Why a weather app is not a briefing#
Most consumer and enthusiast apps display genuine data — they pull the same METARs and TAFs from public feeds. What they usually do not do is guarantee currency, completeness or the inclusion of the warnings, NOTAMs and amendments that a briefing contains. A TAF that was amended eight minutes ago may not have propagated. A SIGMET may not be shown at all. And an aggregated map often silently drops stations whose reports failed to parse.
- No guarantee of currency — feeds lag, and amendments are the ones that matter.
- Warnings often missing — SIGMET and AIRMET coverage in third-party apps is inconsistent.
- No NOTAMs, so a closed runway or an unserviceable approach aid does not appear.
- Silent gaps — a station that failed to parse simply does not show, which looks identical to good weather.
- No record — a briefing you obtained through the official channel is logged; an app screen is not.
None of that makes the apps useless. It makes them a supplement to a briefing rather than a replacement for one, which is exactly how experienced users treat them.
Reading a source critically#
Three questions settle whether what you are looking at can be relied on, and they take about ten seconds.
- Who issued it? A named national service or WAFC, or an aggregator that does not say?
- When was it issued, and what period does it cover? A TAF outside its validity window is history, not forecast.
- Has it been amended? An amended TAF supersedes the original entirely, and amendments cluster exactly when conditions are changing.
If a display cannot answer all three, treat it as an indication and go to the source before it matters.
What this site is, in these terms#
We are none of the above. We do not observe, forecast, relay or aggregate; we explain what the products contain and how to read them, and we link the responsible service for each region so that you can go to it directly. The decoder on our region pages parses text you paste in, in your browser, and never contacts anything.
That is a deliberate boundary. Explaining a report is educational; distributing one carries obligations we are not authorised to take on.
Frequently asked questions
Who provides official aviation weather?
The meteorological authority designated by each state for its own airspace — NOAA’s Aviation Weather Center in the United States, NAV CANADA in Canada, the Met Office in the United Kingdom, DWD in Germany, the IMD in India, REDEMET in Brazil, JMA in Japan, the Bureau of Meteorology in Australia. Above them sit the two World Area Forecast Centres for global upper-air data and nine Volcanic Ash Advisory Centres. There is no single global aviation weather service; the system works because everyone issues the same formats.
Can I use a weather app to plan a flight?
As a supplement, not as the briefing. Most apps show genuine METARs and TAFs, but they rarely guarantee that an amendment has propagated, often omit SIGMETs and AIRMETs entirely, never include NOTAMs, and can silently drop a station whose report failed to parse — which on screen looks exactly like good weather. Flight planning has to rest on an official briefing obtained through the recognised channel for that airspace; the app is for the quick look.
Is aviation weather data free?
Usually yes for the core text products. METARs and TAFs are exchanged internationally under WMO agreements and most national services publish them openly; the United States in particular puts everything on the public web without registration. Graphical products, high-resolution model output and some briefing systems can require an account or a subscription, and a few states restrict access to licence holders. The raw observation and forecast you need to read a situation is almost always free.
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