Pilot guides: aviation weather, explained with worked examples

Every guide below answers a question pilots actually ask — how to read a TAF change group, how much runway a hot day costs, when a small dew-point spread turns into fog — with real reports, the numbers behind them and the mistakes that catch people on checkrides. The examples link to live airport pages so you can check the same thing on today's weather.

• How to Read a TAF Forecast

  Decode a TAF: validity period, FM, BECMG, TEMPO and PROB groups, what each change group promises, and how to pick the worst period for alternate planning. Worked example included.

  Updated 2026-09-27
• Crosswind Component and Runway Selection

  The sine rule, the clock-face shortcut, gust handling and a worked example. How crosswind, headwind and tailwind components decide which runway to use and when to divert.

  Updated 2026-09-27
• QNH, QFE and QNE: Altimeter Settings Explained

  What each altimeter setting measures, when to use which, how to convert hPa and inHg, what a wrong setting does to your altitude, and how transition altitude and level work.

  Updated 2026-09-27
• Dew Point Spread and Fog: Reading the Warning Signs

  What the temperature/dew point spread tells you about fog risk, the difference between radiation, advection and frontal fog, how to read the trend across METARs, and when fog will clear.

  Updated 2026-09-27
• Density Altitude: Hot, High and Humid

  How pressure altitude and temperature combine into density altitude, the rule-of-thumb formula, what it does to take-off roll and climb rate, and how to read it from a METAR.

  Updated 2026-09-27
• METAR Remarks (RMK) Decoded

  The remarks section carries the most precise data in a METAR: sea-level pressure, temperature to a tenth, peak wind, pressure tendency, automated-station codes and recent weather. Here is how to read each group.

  Updated 2026-09-27
• Cloud Layers, Ceiling and Vertical Visibility

  FEW, SCT, BKN and OVC in oktas, which layers count as a ceiling, what VV means, why CB and TCU are the only cloud types reported, and how heights relate to the aerodrome rather than sea level.

  Updated 2026-09-27
• Visibility, RVR and Obscuration Codes

  How prevailing visibility is measured and reported in metres and statute miles, what runway visual range adds, the meaning of P and M prefixes and U/D/N trends, and the difference between mist, fog, haze, smoke, dust and sand.

  Updated 2026-09-27
• Wind Shear, Gusts and Variable Wind

  How the wind group encodes direction, speed, gusts and variability; when a gust factor matters; what WS ALL RWY and WS R24 in a METAR mean; and how low-level wind shear shows up before it is reported.

  Updated 2026-09-27
• Thunderstorms in METAR and TAF

  How thunderstorms are coded in observations and forecasts, the difference between TS, TSRA, VCTS and a CB cloud group, why PROB40 TSRA is a planning problem, and the hazards — downburst, hail, lightning, turbulence — that come with each.

  Updated 2026-09-27
• SIGMET and AIRMET Explained

  What SIGMETs and AIRMETs warn about, who issues them and for which airspace, how to read the location, level and movement groups, the difference between the US and ICAO formats, and how they relate to a METAR or TAF.

  Updated 2026-09-27
• Aircraft Icing: Reading the Warning Signs

  Where airframe icing forms, how to spot it in observations and forecasts (FZRA, FZDZ, FZFG, temperature and dew point, cloud in the freezing band), the difference between rime, clear and mixed ice, and what the freezing level on a meteogram tells you.

  Updated 2026-09-27
• Winds Aloft and Multi-Model Forecasts

  How winds-aloft forecasts are produced, what the major global models (ECMWF, GFS, ICON, GEM, ARPEGE, UKMO) do differently, why consensus beats any single run, and how the Kalynda blend on this site weighs them against live observations.

  Updated 2026-09-27
• How to Read METAR Reports: A Pilot's Guide

  Learn to decode a METAR line by line: station, time, wind, visibility, weather, clouds, temperature, QNH and trend. Worked example plus the mistakes that catch pilots out.

  Updated 2026-09-08
• VFR vs IFR Flight Categories Explained

  What the four flight categories mean, the exact ceiling and visibility thresholds, how to derive them from a METAR or TAF, and how they differ from flight rules and European colour states.

  Updated 2026-09-08

How these guides are written

They are written and reviewed by the pilots and developers who build this site, from the primary standards (ICAO Annex 3, WMO No. 306, FAA FMH-1 and national AIPs) and from operating experience, and they are revised when a standard changes or a reader finds an error. Each one carries its publication and revision dates. Corrections and questions: info@metarandtaf.com. Read more about the site and who runs it.