Look, I get it – METARs and TAFs look like someone smashed their keyboard. But here’s the thing: once you crack the code, they’re actually the most useful weather info you’ll get. Way better than some TV weatherman talking about his weekend plans. These give you exactly what you need to know as a pilot in a compact format.
Quick Answer: METARs report current weather at airports – issued hourly with updates for significant changes. TAFs forecast airport weather for 24-30 hours ahead. Both use standardized codes: airport identifier, time (Zulu), wind direction/speed, visibility, weather phenomena, clouds, temperature/dewpoint, altimeter setting. Learning the common abbreviations takes maybe an hour. After that, you can decode weather anywhere in the world. Every pilot needs to read METARs and TAFs fluently – it’s fundamental for safe flight planning.
METAR Basics
METAR stands for Meteorological Aerodrome Report. It’s a snapshot of current conditions at an airport, issued every hour. If conditions change significantly, they’ll issue a SPECI (special METAR) between regular reports.
METARs follow a strict format worldwide. Once you learn it, you can decode weather reports from airports in Japan, Australia, Europe – anywhere. The format’s the same, just different airport codes. That standardization’s actually pretty useful when you’re flying internationally.
Here’s a real METAR broken down:
METAR KBOS 121551Z 09014G25KT 3SM -RA BR OVC008 06/05 A2990 RMK AO2 PK WND 09031/1534 RAB32 SLP127
Looks like gibberish, right? Let’s decode it piece by piece.
Decoding METAR – Airport and Time
METAR – Just tells you this is a routine report (versus SPECI for a special report).
KBOS – Airport identifier. In the US, it’s “K” plus the three-letter code. KBOS is Boston Logan. International airports drop the K – EGLL for London Heathrow, RJTT for Tokyo.
121551Z – Date and time in Zulu (UTC). “12” is the day of the month, “1551Z” is the time (3:51 PM UTC). Always Zulu time, never local. You’ve gotta convert to local time in your head. East coast US is UTC-5 (or -4 in summer), west coast is UTC-8 (or -7 summer).
Wind Information
09014G25KT – Wind from 090 degrees (east) at 14 knots, gusting to 25 knots.
First three digits are direction (090 = east, 180 = south, 270 = west, 360 = north). Direction is where wind’s coming FROM – 090 means wind from the east blowing toward the west. Next two digits are sustained speed in knots. “G” means gusts, followed by gust speed. “KT” means knots.
If winds are calm, you’ll see “00000KT”. If wind direction varies more than 60 degrees, you might see “VRB05KT” for variable 5 knots. When winds vary significantly, they’ll add something like “090V150” showing wind varying between 090 and 150 degrees.
Pro tip: Look at the difference between sustained winds and gusts. Big spread (like 14 gusting 25) means turbulent conditions. Not fun, especially for landing. Small or no spread means steadier winds.
Visibility and Weather
3SM – Visibility in statute miles. “3SM” means 3 miles visibility. US uses statute miles, most other countries use meters. “9999” in international METARs means visibility greater than 10 km (about 6 miles). Low visibility’s a VFR killer – you need 3 miles for most VFR flight.
-RA BR – Current weather phenomena. This is where it gets interesting. The minus sign means “light.” RA is rain, BR is mist. So “light rain and mist.”
Common weather codes:
– RA = Rain
– SN = Snow
– FG = Fog (visibility less than 5/8 mile)
– BR = Mist (visibility 5/8 to 6 miles)
– HZ = Haze
– TS = Thunderstorm
– SH = Showers
– FZ = Freezing (FZRA = freezing rain – stay home)
– DZ = Drizzle
Intensity prefixes: – (light), no prefix (moderate), + (heavy). So “+TSRA” is heavy thunderstorm with rain. That’s a definite no-go.
Cloud Coverage
OVC008 – Cloud layers. “OVC” means overcast, “008” means 800 feet AGL. So overcast clouds at 800 feet – that’s a low ceiling, marginal VFR at best.
Cloud coverage codes:
– SKC or CLR = Clear (no clouds)
– FEW = Few clouds (1/8 to 2/8 coverage)
– SCT = Scattered (3/8 to 4/8 coverage)
– BKN = Broken (5/8 to 7/8 coverage)
– OVC = Overcast (8/8 coverage)
The three-digit number is cloud height in hundreds of feet AGL. “BKN025” means broken clouds at 2,500 feet. Multiple layers are listed separately: “FEW015 SCT030 BKN045” means few at 1,500, scattered at 3,000, broken at 4,500.
Sometimes you’ll see cloud types: “TCU” means towering cumulus (pre-thunderstorm), “CB” means cumulonimbus (thunderstorm). Avoid these.
Temperature and Dewpoint
06/05 – Temperature 6°C, dewpoint 5°C. Both in Celsius. When temp and dewpoint are close (within 2-3 degrees), expect fog or low clouds. The closer they are, the higher the humidity.
Dewpoint’s actually more useful than temperature sometimes. High dewpoint (above 60°F/15°C) means high humidity and potential for afternoon thunderstorms. Low dewpoint means dry air and good visibility. Spread between temp and dewpoint tells you about fog risk.
Negative temps show with “M” – “M05/M08” means -5°C temp, -8°C dewpoint.
Altimeter Setting
A2990 – Altimeter setting 29.90 inches of mercury. Set this in your altimeter’s Kollsman window. Critical for accurate altitude readings. Never forget to set this before departure – wrong altimeter setting means you’re flying at the wrong altitude.
International METARs use QNH (hectopascals/millibars) instead: “Q1012” means 1012 hectopascals. You need to convert to inches of mercury for US altimeters (divide by 33.86).
Remarks Section
RMK AO2 PK WND 09031/1534 RAB32 SLP127 – Remarks section has additional info. Not always critical, but sometimes important:
– AO2 = Automated station with precipitation sensor
– PK WND 09031/1534 = Peak wind from 090 at 31 knots at 1534Z
– RAB32 = Rain began at 32 minutes past the hour
– SLP127 = Sea level pressure 1012.7 hectopascals
Remarks can include runway visual range (RVR), temperature/dewpoint precision, recent weather, and other observations. Scan them for relevant info but don’t get overwhelmed.
TAF Basics
TAF stands for Terminal Aerodrome Forecast. It’s a weather forecast for an airport, typically covering 24-30 hours. Much longer than a METAR’s snapshot. TAFs help you plan flights – will conditions be good when you arrive? What about for your return?
TAFs use similar codes to METARs but add forecast change indicators. Here’s an example:
TAF KBOS 121720Z 1218/1324 09015G25KT 5SM -RA OVC010
FM130200 27012KT P6SM SCT020 BKN040
TEMPO 1302/1306 4SM -RA BR
Decoding TAF – Header
TAF – Indicates this is a forecast (versus AMD for amended TAF).
KBOS – Airport code, same as METAR.
121720Z – Forecast issued on the 12th at 1720Z.
1218/1324 – Valid period. Forecast is valid from the 12th at 1800Z through the 13th at 2400Z (0000Z on the 14th). That’s the next 30 hours from issuance.
Initial Conditions
09015G25KT 5SM -RA OVC010 – These are the same codes as METARs. Wind from 090 at 15 gusting 25 knots, 5 miles visibility, light rain, overcast at 1,000 feet. This represents conditions for the first period of the forecast.
Forecast Changes – FM (From)
FM130200 – “From” indicates a rapid, complete change in conditions at a specific time. “FM130200” means starting at 0200Z on the 13th, conditions change to what follows.
27012KT P6SM SCT020 BKN040 – New conditions: Wind from 270 at 12 knots, visibility greater than 6 miles (P6SM means “plus 6”), scattered clouds at 2,000, broken at 4,000. Much better conditions.
FM means everything changes at that time – wind, visibility, clouds, everything listed after it. It’s a distinct weather change, like a frontal passage.
Forecast Changes – TEMPO (Temporary)
TEMPO 1302/1306 4SM -RA BR – Temporary conditions expected during the period 0200Z to 0600Z on the 13th. Visibility drops to 4 miles with light rain and mist, but these conditions aren’t expected to last more than an hour at a time and will affect less than half the period.
TEMPO means conditions will temporarily fluctuate to what’s indicated, then return to the prevailing forecast. Think rain showers that come and go.
Forecast Changes – BECMG (Becoming)
Another change indicator is BECMG (becoming). It indicates gradual change over a period:
BECMG 1315/1317 18008KT – Wind gradually becoming 180 at 8 knots between 1500Z and 1700Z. It’s a transition, not a sudden change like FM.
Forecast Changes – PROB (Probability)
PROB40 or PROB30 indicates probability of specific conditions.
PROB30 1310/1314 1SM +TSRA – There’s a 30% chance of visibility dropping to 1 mile with heavy thunderstorms between 1000Z and 1400Z on the 13th. Helps you assess risk.
PROB30 is 30% chance, PROB40 is 40% chance. They don’t forecast below 30% probability in TAFs.
Reading Multiple Layers
TAFs build on each other. The initial forecast continues until a change group (FM, TEMPO, BECMG) modifies it. Let’s walk through this complex TAF:
TAF KSEA 151730Z 1518/1618 20012KT P6SM FEW030 SCT200
FM160000 22015G25KT 4SM -SHRA BKN015 OVC030
TEMPO 1600/1604 2SM TSRA BR BKN008 OVC015CB
FM160400 24020G35KT 3SM -RA OVC012
BECMG 1609/1611 26012KT P6SM NSW SCT020
Breaking it down:
Initial (1518Z-0000Z): Wind 200 at 12 knots, vis 6+ miles, few clouds 3,000, scattered 20,000. Pretty good VFR.
From 0000Z: Wind shifts to 220 at 15 gusting 25, vis drops to 4 miles with light rain showers, broken 1,500, overcast 3,000. Marginal VFR.
Temporary (0000Z-0400Z): Occasional thunderstorms with 2-mile vis, mist, broken 800, overcast 1,500 with cumulonimbus clouds. IFR conditions, don’t fly VFR.
From 0400Z: Wind increases to 240 at 20 gusting 35, vis 3 miles in light rain, overcast 1,200. Still IFR, strong winds.
Becoming (0900Z-1100Z): Gradual improvement to 260 at 12, vis 6+ miles, no significant weather (NSW), scattered 2,000. Back to VFR.
Common Mistakes
Don’t mix up METAR and TAF times. METAR time is when the report was issued. TAF has TWO times – when it was issued, AND the valid period. Read carefully.
Don’t ignore TEMPO or PROB groups because they’re not “prevailing.” That PROB30 thunderstorm? 30% chance is still significant. That TEMPO low visibility? Could be right when you’re trying to land.
Don’t forget to convert Zulu time to local. Rookie mistake is reading a TAF showing good conditions, then realizing that’s 3 AM local time and your actual flight time looks terrible.
Don’t trust old TAFs. They’re issued every 6 hours but conditions change. Always check the most recent TAF and compare to current METARs to see if the forecast is accurate.
Practical Application
Here’s how I actually use these for flight planning:
1. Check departure METAR: Current conditions at my airport. Can I depart legally and safely?
2. Check destination METAR: Current conditions where I’m going. What’s it like right now?
3. Check departure TAF: Will conditions deteriorate while I’m gone? Do I have a legal alternate to return to?
4. Check destination TAF: What will conditions be when I arrive? Any TEMPO or PROB groups during my ETA?
5. Check en route METARs: Airports along my route – are conditions widespread or localized? Helps identify fronts, weather systems.
6. Check alternate airports: If destination weather craps out, where can I divert? Check their METARs and TAFs.
I also compare TAF to actual METAR evolution. Is the TAF accurate? If the forecast showed clearing but METARs show deteriorating conditions, I don’t trust the TAF for future periods. Trust observed trends over forecasts when they conflict.
Additional Resources
AviationWeather.gov has decoded METARs and TAFs if you want to check your interpretation. Super useful when learning. ForeFlight and Garmin Pilot decode them automatically – helpful, though I think you should learn to read raw reports first.
1800wxbrief.com phone briefers will decode everything for you and explain conditions. Great when you’re new or conditions are complex. But don’t become dependent – briefers aren’t always available, and you need to read weather reports independently.
Practice with real-world METARs and TAFs every day, even when you’re not flying. Pick a random airport, decode the weather, think about whether you’d fly there. Builds proficiency fast.
Final Thoughts
Real talk – learning METARs and TAFs is non-negotiable. You can’t be a safe pilot without reading weather fluently. Yeah, it’s a weird code that takes effort to learn. But after you decode maybe 50-100 reports, it becomes automatic. You’ll glance at a METAR and instantly know the conditions.
The standardization means this skill is universal. Whether you’re flying in Alaska, Florida, France, or Australia, weather reports follow the same format. Learn it once, use it forever. That’s a pretty good return on investment for maybe 2-3 hours of study.
Don’t rely on decoded weather or apps to do it for you. Technology fails. Internet goes down. Understand the raw reports. It might save your life when your iPad dies and you’re trying to decide if you can legally land somewhere. Master METARs and TAFs – it’s fundamental airmanship.
Leave a Reply