Decoding a METAR: a 5-minute guide for VFR pilots

A METAR is a snapshot of weather at one airport, encoded in a deliberately compact format. Once you can read one, you can read every METAR in the world — the format is standardized internationally. The bad news is that a METAR is dense; the good news is that for VFR pilots, only four fields drive 90% of go/no-go decisions. This is the practical guide.

A real example, decoded

Here's a real METAR from LIRP (Pisa) at 14:50 UTC:

LIRP 141450Z 24008KT 9999 FEW025 SCT100 17/09 Q1018 NOSIG

Read left to right:

| Token | Meaning | |---|---| | LIRP | Station: Pisa, Italy | | 141450Z | Day 14, time 14:50 UTC ("Z" = Zulu) | | 24008KT | Wind from 240° at 8 knots | | 9999 | Visibility 10+ km (the "M" in 9999 means "more than") | | FEW025 | Few clouds at 2,500 ft | | SCT100 | Scattered clouds at 10,000 ft | | 17/09 | Temperature 17°C / dew point 9°C | | Q1018 | QNH altimeter 1018 hPa | | NOSIG | No significant change expected for the next 2 hours |

That's a perfect VFR day. Wind manageable, vis 10+ km, only "few" low clouds, big temp/dew spread, stable QNH. Go.

Now decode each field properly.

Wind: where, how strong, and gusts

24008KT — wind from 240° true (so south-southwest, since 360° = north) at 8 knots steady.

Variants you'll see:

• VRB05KT — variable direction at 5 kt (light wind, no clear bearing)
• 27015G25KT — from 270° at 15 kt, gusting to 25 kt
• 27015KT 240V300 — from 270° at 15 kt, varying between 240° and 300°

For a UL pilot, the gust factor is what matters. A 8 kt steady wind is a non-event; an 8G18 wind means real bumps. The general "go/no-go" threshold for an unfamiliar UL pilot:

• Wind speed: ≤15 kt steady
• Gust spread: ≤7 kt (e.g., 10G15 is OK, 10G20 is borderline)
• Crosswind component: within demonstrated max of the airframe

For the Tecnam P92 Echo MkII, demonstrated crosswind is 16 kt, so a 90° crosswind from 27015KT at a runway 18/36 is at the limit but flyable. Compute crosswind as windspeed × sin(angle_offset_runway).

Visibility: the most important number

9999 = 10+ km. That's the upper end of what METAR reports.

Real visibility values you'll see:

• 9999 — 10+ km, perfect VFR
• 8000 — 8 km, fine VFR
• 5000 — 5 km, minimum VFR in most airspaces
• 1500 — 1.5 km, IFR territory
• 0500 — 500 m, low IFR; only flying for type-rated IR pilots in IFR-certified aircraft

For UL/LSA flying, the legal minimum is typically 5 km in uncontrolled airspace and 1.5 km IFR-only conditions. National rules vary; check yours.

If visibility is between 1.5 and 5 km, METAR appends a weather code explaining why — BR (mist), FG (fog), RA (rain), HZ (haze), etc.

Weather phenomena codes

After visibility you might see weather phenomena:

• RA rain · SN snow · BR mist · FG fog · HZ haze
• TS thunderstorm · SH shower (e.g., SHRA = rain shower)
• Intensity: +RA heavy rain · -RA light rain · RA moderate
• Proximity: VC (in vicinity, within 8 km but not at field)

For VFR pilots, TS, +TSRA, +SN, FG are go/no-go flags. Light rain (-RA) is usually fine for VFR; heavy rain (+RA) often comes with reduced visibility and reduced engine performance. Thunderstorms — never within 20 nm.

Clouds: layers, types, ceiling

Cloud groups have a coverage code + altitude in hundreds of feet AGL:

• SKC — sky clear, no clouds (rare in METAR; usually means automated stations)
• FEW010 — few clouds (1/8 to 2/8 sky cover) at 1,000 ft
• SCT025 — scattered (3/8 to 4/8) at 2,500 ft
• BKN040 — broken (5/8 to 7/8) at 4,000 ft
• OVC080 — overcast (8/8) at 8,000 ft

The ceiling is the lowest BKN or OVC layer. A BKN015 METAR means the ceiling is 1,500 ft AGL — your VFR altitude is constrained, and you may not have legal VFR cloud separation in many airspaces.

For UL pilots cruising at 1,500-3,000 ft AGL typical:

• FEW and SCT at 4,000+ ft = no problem
• BKN030 = practical ceiling at ~3,000 ft, room to fly underneath
• OVC020 = ceiling at 2,000 ft, IFR conditions for most VFR pilots

Temperature and dew point: the spread

17/09 — air 17°C, dew point 9°C, spread of 8°C.

The temperature/dew point spread is the fog risk indicator:

• Spread > 5°C: stable, no fog risk in the next 2 hours
• Spread 2-5°C: visible moisture (haze, possible fog with overnight cooling)
• Spread < 2°C: fog imminent (within ~15 minutes)
• Spread = 0 (e.g., 17/17): fog already present

Negative dew point + low temperature = ice risk. M02/M05 (minus 2°C / minus 5°C) means structural icing is possible if you fly into clouds. UL pilots flying day-VFR usually avoid this; it's an IFR pilot's concern.

QNH: the altimeter setting

Q1018 — set your altimeter to 1018 hPa to read the published field elevation correctly.

Some countries publish in inHg (Q vs A): A2992 means 29.92 inHg. The conversion: 1 inHg = 33.86 hPa.

The QNH is what you set when departing or arriving at that airport. For climb-out and en-route flying above transition altitude, you switch to standard pressure 1013 hPa (29.92 inHg).

NOSIG, BECMG, TEMPO

Trailing codes describe expected change:

• NOSIG — no significant change in the next 2 hours
• BECMG 1418 27015KT — wind will become 270/15 between 14:00 and 18:00
• TEMPO 1216 -RA BKN030 — temporary (less than 1 hour) period between 12:00 and 16:00 with light rain and broken clouds at 3,000 ft

For VFR pilots, TEMPO items are the cautionary flags — even if current conditions are fine, the temporary phenomena might catch you en-route.

The 4 fields that drive 90% of VFR decisions

In order of priority:

1. Visibility — is it ≥ legal minimum + comfort margin?
2. Wind (especially gust factor) — within airframe and pilot demonstrated?
3. Ceiling (lowest BKN/OVC) — can I fly safely under or above it?
4. Weather phenomena — TS, +RA, SN, FG present or in vicinity?

If all four are green, the rest of the METAR is detail. If any one is red, it's a no-go regardless of how nice the others look.

How to use METAR in route planning

Voliqo's planner pulls METARs for your departure, intermediate stops, and destination. Each station's reading appears next to the airport on the map and in the route summary. For multi-leg routes, check each station's METAR — a fine-weather departure into a marginal destination is the most common pilot trap.

For more on TAFs (forecasts vs current reports) see the next post in this series, Decoding a TAF.

Bottom line

A METAR is dense but not complicated. Practice on three or four real stations a day for a week and you'll read them faster than your morning text messages. The four-field heuristic — visibility, wind, ceiling, weather phenomena — gets you 90% of the way to a go/no-go decision; the rest is detail.

For VFR pilots, the discipline is: read the METAR before opening the hangar door, not after.