TAF decoder, free, in plain English
Paste any TAF and this decoder reads it back to you period by period, so you can see which forecast applies when.
Group 3 of 24, issue time
Issued on the 8th at 05:00 UTC.
This is when the forecaster wrote the forecast, not when it starts. The forecast usually starts a little after it was issued, which is what the next group tells you.
Exam trap: The issue time is not the start of the validity. Reading the first time group as the start of the forecast puts every later timing answer out by an hour or more.
In plain English.
Delhi Indira Gandhi. Issued on the 8th at 05:00 UTC. Valid from the 8th at 0600 UTC to the 9th at 1200 UTC.
Wind from 90 at 6 knots. Visibility 4 km. Haze. Scattered at 2,500 ft.
Becoming, between the 8th at 1000 UTC and the 8th at 1200 UTC: Wind from 120 at 8 knots. Visibility 5 km.
Temporarily, between the 8th at 1800 UTC and the 8th at 2100 UTC: Visibility 2 km. Mist. Broken at 1,500 ft.
30% chance, between the 8th at 2100 UTC and the 9th at 0300 UTC: Visibility 500 m. Fog. Sky obscured, vertical visibility 200 ft.
From the 9th at 04:00 UTC: Wind from 270 at 4 knots. Visibility 3 km. Mist. Scattered at 2,000 ft.
Example reports, not live weather.
Group by group.
How to decode a TAF, line by line.
An example for Delhi in winter, the one the decoder opens on: TAF VIDP 080500Z 0806/0912 09006KT 4000 HZ SCT025 BECMG 0810/0812 12008KT 5000 TEMPO 0818/0821 2000 BR BKN015 PROB30 0821/0903 0500 FG VV002 FM090400 27004KT 3000 BR SCT020
- 1Read the header
TAF VIDP 080500Z
A forecast for Delhi (VIDP), issued on the 8th at 0500 UTC. Every time in a TAF is UTC, never IST.
- 2Read the validity
0806/0912
It runs from the 8th at 0600 UTC to the 9th at 1200 UTC. Nothing in it applies outside that window.
- 3Read the base forecast
09006KT 4000 HZ SCT025
Wind from 090 degrees at 6 knots, 4,000 metres in haze, scattered cloud at 2,500 feet. This holds until a change group says otherwise.
- 4Read BECMG as a lasting change
BECMG 0810/0812 12008KT 5000
Between 1000 and 1200 UTC the wind becomes 120 degrees at 8 knots and visibility 5,000 metres, and stays that way. Only the groups it names change.
- 5Read TEMPO as a temporary spell
TEMPO 0818/0821 2000 BR BKN015
Between 1800 and 2100 UTC there are spells of 2,000 metres in mist under broken cloud at 1,500 feet, and the forecast before them resumes after. The exam trap is reading TEMPO as a lasting change.
- 6Read PROB as a probability
PROB30 0821/0903 0500 FG VV002
A 30 per cent chance, from 2100 UTC on the 8th to 0300 UTC on the 9th, of 500 metres in fog with the sky obscured and a vertical visibility of 200 feet. PROB is only ever 30 or 40.
- 7Read FM as a fresh start
FM090400 27004KT 3000 BR SCT020
From 0400 UTC on the 9th everything before it is replaced: wind 270 degrees at 4 knots, 3,000 metres in mist, scattered cloud at 2,000 feet. FM carries no leftovers, unlike BECMG.
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