The METAR Decoded - Reading a Weather Observation Left to Right and the Go-No-Go Decision Hidden Inside

A METAR (Meteorological Aerodrome Report) is one of the most powerful weather tools available to pilots, and one of the most underused. Most student pilots learn to scan for ceiling and visibility and stop there - but the full report contains a detailed weather picture that can make or break a go-no-go call. Read left to right, every field tells you something.

The example used throughout this article: KORF 261555Z 09012KT 10SM OVC010 18/16 A2992 RMK AUTO SLP1014

What Does the Station Identifier Tell You?

Every METAR in the contiguous United States begins with K, followed by a three-letter airport identifier. In this example, KORF is Norfolk International Airport in Virginia. Before you read anything else, confirm you pulled the right station. It sounds obvious, but planning a flight on another airport’s weather is a real mistake that happens to real students.

How Do You Read the Date and Time Group?

261555Z breaks into three parts. 26 is the day of the month. 1555 is the time in Zulu (UTC) - 15:55, or 3:55 PM universal time. The Z confirms the time zone. All METARs worldwide use the same clock, which is why Zulu matters when comparing reports across time zones or planning a cross-country.

Routine METARs are typically issued at :55 past the hour at automated stations. If you see SPECI at the front of a METAR instead of the normal station type, conditions changed significantly enough to trigger a special observation before the next scheduled report. Treat a SPECI as a flag worth examining closely.

How Do You Read Wind in a METAR?

09012KT packs three pieces of information into one group. The first three digits are wind direction: 090 means wind from the east (from 090 degrees). Wind direction is always the direction the wind is coming from, not blowing toward.

The next two digits are wind speed: 12 knots. If the report included gusts, you’d see a G - for example, 18015G25KT means wind from 180° at 15 knots, gusting to 25 knots. Gusts demand attention on approach because they affect both airspeed management and energy control on final.

When wind is light and variable (generally under 6 knots), the direction field shows VRB instead of degrees. VRB03KT means the wind is shifting unpredictably at 3 knots. On a hot afternoon with thermals building, variable winds can signal deteriorating conditions ahead.

What Does Visibility Mean in a METAR - and Why Statute Miles?

10SM means 10 statute miles visibility. The FAA reports horizontal visibility in statute miles, not nautical. Basic VFR requires 3 statute miles in most airspace - Class B, C, and D all share that threshold.

Reduced visibility appears as fractions: 1/4 SM or 1/2 SM. Below a quarter mile, the report may read M1/4SM (less than one quarter). In those conditions, VFR operations aren’t on the table. A mixed value like 2 1/2 SM is common in haze or light fog that isn’t zero-zero but isn’t good either.

What Do Present Weather Codes Mean?

Between visibility and sky condition, you may find abbreviations for what’s currently falling or reducing visibility. Common ones:

• RA - rain
• SN - snow
• FG - fog (visibility at or below 5/8 statute mile)
• BR - mist (visibility between 5/8 and 6 statute miles)
• DZ - drizzle
• TS - thunderstorm; combinations like TSRA mean thunderstorm with rain
• + prefix = heavy; − prefix = light; no modifier = moderate

The FG vs. BR distinction matters for go-no-go. Mist still allows VFR. Fog does not. In the example METAR, there’s no present weather code - no precipitation, no obscuring phenomena at the time of observation.

How Do You Determine the Ceiling from a METAR?

OVC010 means overcast at 1,000 feet AGL (the three digits represent hundreds of feet). Sky condition is reported in eighths of coverage:

Broken and overcast layers define the ceiling. Few and scattered do not. This distinction has real consequences. A few layer at 800 feet with an overcast at 3,000 feet means your ceiling is 3,000 feet - the few layer doesn’t count. But if that few layer becomes broken, your ceiling drops to 800 feet, and you may be in controlled airspace below legal VFR minimums.

When multiple layers exist, they appear stacked in order from lowest to highest. Read all of them. OVC010 at Norfolk puts conditions right at the edge of VFR minimums in controlled airspace. Before launching, check whether that ceiling is rising or falling.

What Do Temperature and Dewpoint Tell You?

18/16 means temperature 18°C, dewpoint 16°C. The two-degree spread is the critical detail here. When temperature and dewpoint are within 2–3°C of each other, fog or low clouds are likely forming or imminent - especially overnight when temperatures drop to meet the dewpoint.

Temperature also affects density altitude. As temperature rises above the standard atmosphere, density altitude increases - your aircraft performs as if it’s at a higher elevation. That means a longer takeoff roll, reduced climb rate, and less engine thrust. On any warm day, calculate density altitude before departure. It’s an ACS task for a reason, and it’s operationally relevant every summer flight.

How Do You Use the Altimeter Setting and Remarks?

A2992 means set your altimeter to 29.92 inches of mercury. You’re required to update it when within 100 nautical miles of a reporting station in controlled airspace. On the ground, confirm the altimeter matches field elevation within approximately 75 feet. A wrong setting puts you at a different altitude than your instrument reads - critical on any approach, and significant near terrain on a VFR flight.

The RMK section is where many pilots stop reading. Don’t. Remarks contain some of the most useful information in the entire report.

AUTO means this is an automated station with no human observer. Automated sensors can miss certain phenomena: virga, partial obscurations, and developing conditions a trained observer would catch. In marginal conditions at an automated station, apply extra skepticism.

SLP1014 is sea level pressure in millibars - 1,014 mb in this case. Other common remarks to know:

• T followed by 8 digits - precise temperature and dewpoint to tenths of a degree
• PK WND - peak wind during the past hour, including time of occurrence
• LTNG - lightning observed in the vicinity
• RVR - runway visual range, reported in hundreds of feet, critical for instrument approaches

How Do You Make a Go-No-Go Decision from a METAR?

Putting the Norfolk METAR together: winds from the east at 12 knots, visibility 10 miles, overcast at 1,000 feet, temperature 18°C, dewpoint 16°C, altimeter 29.92, automated station.

The picture: ceiling is at or near VFR minimums. The tight temperature-dewpoint spread flags possible fog development, especially coastal. Visibility is acceptable now but could close quickly. Winds are steady and manageable.

This is not a “no-go” by itself - but it’s not a comfortable “go” either. The right move is to look at trend. Pull METAR history for the past four to six hours. Is the ceiling lifting or lowering? Is the spread tightening? Are there AIRMETs or SIGMETs for IFR conditions in the region? A single METAR is a snapshot. Weather is a movie. One frame isn’t enough to make a fully informed decision.

Build the habit of reading METARs in sequence at your destination and along your route. Watch what the ceiling does overnight, how the spread changes as temperatures drop, how winds shift ahead of a front. After a few months of this, you develop genuine intuition - you start to see what’s coming, not just what’s there right now.

On the checkride, the examiner will hand you a METAR and ask what kind of day it is and whether you’d go. They’re not looking for a recitation of codes. They want your decision, backed by your understanding of the data. That’s the skill being tested.

Key Takeaways

• Read a METAR left to right: station ID → date/time (Zulu) → wind → visibility → present weather → sky condition → temperature/dewpoint → altimeter → remarks
• Broken and overcast layers define the ceiling; few and scattered do not - a BKN layer can change your legal minimums instantly
• A temperature-dewpoint spread of 2–3°C or less signals fog or low cloud formation is likely
• The RMK section contains critical data - automated station status, sea level pressure, peak winds, and lightning observations
• One METAR is a snapshot; always check trend and context before making a go-no-go call