The METAR, the Coded Surface Observation Every Student Retrieves and Most Only Half-Read, and the Remarks Section That Changes the Picture

A METAR packs a complete surface weather picture into a single line of coded text. Most pilots read as far as the altimeter setting and stop there - but the remarks section that follows contains critical details about precipitation type, peak wind events, pressure trends, and station limitations that can change a go/no-go decision. Reading a METAR means reading all of it.

What Is a METAR and How Often Is It Updated?

The Meteorological Aerodrome Report is a standardized surface weather observation issued every hour at most airports, and every 20 to 30 minutes at busier fields. The observation is generated either by a certified weather observer or an automated station. That distinction is encoded in the observation itself, and it matters.

How to Decode a METAR: A Complete Field-by-Field Example

This is a realistic METAR that covers every major element:

KJAN 2354Z 14009G18KT 1 1/2SM +RA BR BKN008 OVC020 13/11 A2972 RMK AO2 P04 SLP254

Every piece of that string has a specific meaning. Here’s how to read it from front to back.

How Do You Decode the Station Identifier and Observation Time?

KJAN is Jackson, Mississippi. In the contiguous United States, station identifiers are four letters beginning with K. Alaska uses PA, Hawaii uses PH, and Canada uses C. International stations follow mostly the same format but may have minor differences.

2354Z is the observation time: 2354 Zulu, or Coordinated Universal Time (UTC). Aviation runs on Zulu time universally. In the Central time zone during standard time, you’re five hours behind Zulu - so this observation was taken at 5:54 PM local. Misreading the Zulu offset can cause you to act on a stale observation, so know your offset before you brief.

How Do You Read Wind Speed and Gusts in a METAR?

14009G18KT breaks down as: wind from 140 degrees magnetic (roughly southeast), at 9 knots, gusting to 18 knots.

The gust value is the number that matters for your approach. Your aircraft responds to the gust, not the steady wind. If you’re flying a Cessna 172 with a demonstrated crosswind component of 15 knots and the surface wind is 9 gusting 18, the steady state looks manageable - but the gust pushes you past the aircraft’s limit. Always calculate your crosswind component using the gust value.

Variable winds appear as VRB before the speed. VRB03 means variable direction at 3 knots - usually minor. Variable winds at higher speeds can indicate convective activity or outflow from nearby weather.

What Does METAR Visibility Mean for VFR Flight?

1 1/2SM means one and a half statute miles. The United States reports visibility in statute miles. When visibility is ten miles or greater, it’s reported as P10 (plus ten).

One and a half miles puts you in MVFR (Marginal Visual Flight Rules) territory. VFR generally requires at least 3 statute miles visibility and a ceiling above 1,000 feet, though exact requirements depend on airspace. Marginal conditions are dynamic - the METAR tells you current conditions, not whether they’re improving or deteriorating. For trend information, pair the METAR with the TAF and several preceding observations.

How Do You Decode Present Weather Codes?

+RA BR means heavy rain and mist. The plus sign is the intensity modifier for heavy. A minus sign means light; no modifier means moderate.

Common weather codes to know:

• RA - rain
• SN - snow
• DZ - drizzle
• FG - fog
• BR - mist
• TS - thunderstorm
• FZ prefix - freezing (FZRA = freezing rain)
• IC - ice crystals

TS in a METAR means a thunderstorm is occurring at or near the airport - significant regardless of what else the observation shows. VCTS means thunderstorm in the vicinity, within roughly five to ten miles. Vicinity is not far away. Vicinity can mean your traffic pattern.

How Do You Determine Ceiling from Sky Condition Codes?

BKN008 OVC020 reports two cloud layers: a broken layer at 800 feet AGL and an overcast at 2,000 feet AGL.

Sky coverage codes:

• FEW - 1/8 to 2/8 coverage
• SCT - 3/8 to 4/8 (scattered)
• BKN - 5/8 to 7/8 (broken)
• OVC - 8/8 (overcast)
• SKC - sky clear

The ceiling is the lowest broken or overcast layer. In this example, that’s 800 feet - IFR conditions. Scattered layers are not ceilings. A scattered layer at 800 feet does not make the ceiling 800 feet. A broken layer at 800 feet does. The threshold is five-eighths coverage or more. That will come up on your checkride.

CB (cumulonimbus) or TCU (towering cumulus) appended to a sky condition code is an immediate red flag. BKN050CB means a broken layer of cumulonimbus at 5,000 feet - a thunderstorm environment that overrides everything else in the observation.

What Do Temperature and Dewpoint Tell You?

13/11 means temperature 13°C (about 55°F) and dewpoint 11°C - a spread of only 2 degrees.

The temperature-dewpoint spread, called the dewpoint depression, tells you how close the air is to saturation. When that spread closes to 2 degrees or less, fog or low cloud formation becomes likely. If you’re planning an early morning departure and the spread is this tight at sunset, expect visibility issues by dawn. This is one of the most practical early-warning signals in the entire METAR, and it’s easy to miss.

Temperature and dewpoint also affect density altitude. On a warm, humid day, your actual performance - takeoff roll, climb rate, fuel burn - will be worse than field elevation alone suggests.

What Does the Altimeter Setting Mean?

A2972 means the current altimeter setting is 29.72 inHg. Set this in your altimeter window before flight to get an accurate altitude reading. Standard atmosphere is 29.92 inHg.

At 29.72, pressure is below standard. The memory aid applies: “Low pressure, low altitude, look out below.” True altitude is lower than indicated. Set your altimeter at every airport you transition through, not just departure.

What Is in the METAR Remarks Section and Why Does It Matter?

The remarks section begins with RMK. Most pilots stop reading at the altimeter setting. That’s where the most operationally specific information often starts.

In this example, the remarks are AO2 P04 SLP254.

AO2 means the station is an automated observing station with a precipitation discriminator - it can distinguish rain from snow. AO1 can detect precipitation but cannot identify the type. If you see AO1 in the remarks and the weather field shows precipitation, that type is inferred, not confirmed. That distinction matters when icing is a concern.

P04 is hourly precipitation accumulation: 0.04 inches of rainfall in the last hour. Not heavy, but active - confirming the +RA in the weather field is real, ongoing precipitation.

SLP254 is sea level pressure: 1025.4 millibars. Watching how this value trends across successive METARs tells you whether conditions are building or eroding before you look at a prog chart. High pressure brings stable air; low pressure brings weather.

Other remarks worth knowing:

• T followed by digits - precise temperature and dewpoint to the nearest tenth of a degree
• PKWND - peak wind, with direction, speed, and the time it occurred
• LIGHTNING - lightning detected in the area
• SNINCR - snow increasing rapidly
• RAB35 - rain began at 35 minutes past the hour (BEG = began, END = ended)

Peak wind deserves specific attention. If your steady wind is 12 knots but the remarks show a 34-knot peak earlier in the hour, that spike belongs in your planning even if conditions appear calm at brief time.

What Is the Right Order to Read a METAR?

Reading a METAR in a consistent sequence ensures nothing gets missed:

1. Station and time - Is this observation current? An observation more than an hour old during changing conditions is stale.
2. Wind - Direction, speed, and gust. Calculate crosswind using the gust value.
3. Visibility - Are you above VFR minimums and your personal minimums?
4. Present weather - Any precipitation? Any thunderstorm indicators?
5. Sky condition - What is the actual ceiling? Not the scattered layer - the ceiling.
6. Temperature and dewpoint - Is the spread closing toward fog or low clouds?
7. Altimeter - Set it.
8. Remarks - Read every word.

That full sequence takes about 45 seconds with practice. It gives you a complete picture of conditions at that airport within the last hour.

What Are the Limitations of Automated Weather Stations?

Automated stations are accurate for most parameters, but they have documented limitations. They can miss cumulonimbus in certain configurations and cannot observe what a trained human observer would catch - a thickening haze layer, a virga curtain on the horizon, or rapidly changing conditions at the field edge.

If you’re flying into a remote airport with an AO1 or AO2 station during rapidly changing weather, treat the observation as useful but incomplete. PIREPs (Pilot Weather Reports) from aircraft in the area can fill in what automated stations miss. Seek them out when the situation is developing.

How Does the METAR Fit Into the Broader Weather Picture?

The METAR tells you what was happening at one specific airport within the last hour. It is one piece of a briefing, not a substitute for one.

• TAF - Terminal Aerodrome Forecast: expected conditions at that airport
• Winds Aloft - conditions at altitude
• Graphical Forecast for Aviation (GFA) - regional picture
• Area Forecast Discussion (AFD) - the forecaster’s plain-language reasoning behind all the products

The AFD is one of the most underused products in general aviation. It surfaces the uncertainties and judgment calls that official products don’t show. Read the products together. Relying on any single one in isolation means working with an incomplete picture.

The Aviation Weather Center at aviationweather.gov has a plain-language METAR decoder and complete documentation for every field and remark code. The FAA’s Aviation Weather Handbook is a free document that covers all of it in detail.

Key Takeaways

• The METAR remarks section - everything after RMK - contains critical information most pilots never read, including station type, precipitation totals, peak winds, and sea level pressure trends.
• Always calculate crosswind component using the gust value, not the steady-state wind speed.
• A scattered cloud layer is not a ceiling. Ceiling is defined by the lowest broken or overcast layer - five-eighths coverage or more.
• A temperature-dewpoint spread of 2°C or less signals potential fog or low cloud formation and is a key early warning for dawn departures.
• AO1 stations cannot confirm precipitation type. If icing is a concern and the remarks show AO1, the precipitation type in the weather field is inferred, not observed.