<h2>What Is a METAR?</h2> <p> METAR stands for Meteorological Aerodrome Report. Issued every hour (and more frequently as SPECI reports when conditions change rapidly), METARs are the backbone of aviation weather worldwide. Every automated weather station, every ATC facility, and every weather product you use — including <a href="https://droneskycast.com/dashboard">DroneSkycast's real-time checks</a> — ultimately traces its data back to METAR observations. </p> <p> As a drone pilot operating under FAA Part 107, you are not legally required to file a weather briefing the way manned-aircraft pilots are, but the information in a METAR directly determines whether your planned operation is legal and safe. Understanding the raw format lets you catch conditions that automated systems might miss or simplify. </p> <h2>A Real METAR Decoded Field by Field</h2> <p>Here is a real-world example we will break down completely:</p> <div class="callout"> <p><strong>METAR KLAX 121755Z 25012KT 10SM FEW030 SCT120 22/14 A2992</strong></p> </div> <h3>Field 1 — Report Type: METAR</h3> <p> The report type is either <strong>METAR</strong> (routine hourly observation) or <strong>SPECI</strong> (special observation). A SPECI is issued automatically when visibility drops below a threshold, ceiling drops below a threshold, or weather phenomena such as thunderstorms begin or end. If you see SPECI in your pre-flight data, treat it as a signal that conditions are actively changing and check whether the change improves or deteriorates the situation. </p> <h3>Field 2 — Station Identifier: KLAX</h3> <p> The four-character ICAO code identifies the observing station. All US stations begin with K. KLAX is Los Angeles International Airport. METARs are issued at airports, so the observation is always for conditions at ground level at that airport. For a drone operation five miles from the airport, conditions may differ — particularly for wind speed and direction over complex terrain. </p> <h3>Field 3 — Observation Time: 121755Z</h3> <p> The format is DDHHMMz, where DD is the day of the month, HH is the hour in UTC (Zulu), and MM is the minute. <strong>121755Z</strong> means the 12th day of the month at 17:55 UTC. In Los Angeles (UTC−7 during PDT), that is 10:55 AM local time. Always check how old the observation is. A METAR issued 55 minutes ago in a fast-moving frontal situation can be significantly stale. The next hourly METAR will arrive around 18:55Z. </p> <h3>Field 4 — Wind: 25012KT</h3> <p> Wind is reported as a three-digit true direction (the direction the wind is blowing <em>from</em>) followed by a two-digit speed, followed by the unit KT (knots). <strong>25012KT</strong> means wind from 250° (roughly west-southwest) at 12 knots. </p> <p> If gusts are present, you will see a G before the gust speed: <strong>25012G22KT</strong> means average 12 knots with gusts to 22 knots. For drones, <strong>gusts are the critical number</strong>, not the average. A DJI Mini 3 Pro has a maximum wind resistance of 10.7 m/s (approximately 21 knots). A steady 12-knot wind is well within limits, but 22-knot gusts exceed them. </p> <p> Variable wind direction with speed below 6 knots is reported as VRB03KT. If the direction is variable but speed is higher, you will see something like 25012KT 220V280, meaning the wind is oscillating between 220° and 280°. </p> <div class="callout callout-warn"> <p> <strong>Unit conversion note:</strong> METARs use knots (nautical miles per hour). DJI specifications use m/s. Multiply knots by 0.514 to get m/s, or divide m/s by 0.514 to get knots. 10.7 m/s ≈ 20.8 knots. </p> </div> <h3>Field 5 — Visibility: 10SM</h3> <p> In US METARs, prevailing visibility is reported in statute miles. <strong>10SM</strong> is the maximum reportable value and means visibility is ten or more statute miles — essentially unlimited for practical purposes. </p> <p> Under FAA Part 107, the minimum visibility for sUAS operations in Class G airspace is 3 statute miles. In controlled airspace (Classes B, C, D, and E at surface level), the same 3SM minimum applies. Any METAR showing visibility below 3SM means your operation is grounded without a waiver, regardless of what the weather looks like to the naked eye. </p> <p> If you see RVR instead of SM values during low-visibility conditions (e.g. <strong>R26L/2400FT</strong>), that is Runway Visual Range in feet and indicates IMC conditions well below any sUAS legal threshold. </p> <h3>Field 6 — Sky Condition: FEW030 SCT120</h3> <p> Sky condition groups are reported as a coverage code plus height in hundreds of feet above ground level (AGL). This METAR has two layers: </p> <ul> <li><strong>FEW030</strong> — few clouds (1–2 oktas of sky covered) at 3,000 ft AGL</li> <li><strong>SCT120</strong> — scattered clouds (3–4 oktas) at 12,000 ft AGL</li> </ul> <p>Coverage codes and their meanings:</p> <table> <thead><tr><th>Code</th><th>Coverage</th><th>Oktas</th></tr></thead> <tbody> <tr><td>SKC / CLR</td><td>Clear</td><td>0</td></tr> <tr><td>FEW</td><td>Few</td><td>1–2</td></tr> <tr><td>SCT</td><td>Scattered</td><td>3–4</td></tr> <tr><td>BKN</td><td>Broken</td><td>5–7</td></tr> <tr><td>OVC</td><td>Overcast</td><td>8</td></tr> </tbody> </table> <p> For Part 107 operations, the operative requirement is cloud clearance. You need at least 500 ft <em>below</em> the lowest layer and 2,000 ft above. With FEW030, you must stay below 2,500 ft AGL — but since Part 107 caps you at 400 ft AGL anyway (or 400 ft above a structure), that leaves a 2,100 ft buffer in this example. The ceiling only becomes a factor when it drops below 900 ft AGL, at which point your legal 400 ft ceiling and required 500 ft separation would overlap. </p> <h3>Field 7 — Temperature/Dewpoint: 22/14</h3> <p> Temperature and dewpoint in Celsius, separated by a slash. In our example, the air is 22°C (72°F) with a dewpoint of 14°C (57°F). The <strong>spread</strong> between these values determines relative humidity and fog risk. A spread of 8°C here is comfortable. If the spread were 2°C or less, expect fog or low stratus to form within one to two hours, especially after sunset when temperatures fall. </p> <p> Dewpoint also affects battery performance. At low temperatures, particularly below 5°C, LiPo cells lose capacity rapidly. DroneSkycast's scoring system applies a temperature penalty that accounts for battery degradation in cold conditions. </p> <h3>Field 8 — Altimeter: A2992</h3> <p> The altimeter setting is the local sea-level pressure expressed in inches of mercury, prefixed with A. <strong>A2992</strong> means 29.92 inHg — coincidentally the international standard atmosphere value. This matters for drone pilots because many GPS-enabled drones use barometric pressure to hold altitude. Significant departures from standard (e.g., A2960 or A3020) mean the drone's barometric altimeter reads an altitude that differs from true AGL altitude by up to 50–100 ft. </p> <h2>Remarks Section (RMK)</h2> <p> After the main body, a METAR may include a remarks section starting with RMK. Common drone-relevant remarks include: </p> <ul> <li><strong>SLP018</strong> — sea-level pressure (used to calculate density altitude)</li> <li><strong>T02220144</strong> — precise temperature/dewpoint to tenths of a degree</li> <li><strong>TSNO</strong> — thunderstorm detection equipment not available</li> <li><strong>TS B15</strong> — thunderstorm began at minute 15 past the hour</li> </ul> <h2>Present Weather Codes</h2> <p> If the METAR includes weather phenomena between the visibility and sky condition fields, they are encoded as two-letter descriptors. Key ones for drone pilots: </p> <table> <thead><tr><th>Code</th><th>Meaning</th><th>Drone Impact</th></tr></thead> <tbody> <tr><td>TS</td><td>Thunderstorm</td><td>Absolute no-fly; instant NO_GO in DroneSkycast</td></tr> <tr><td>RA</td><td>Rain</td><td>Risk to electronics; score penalty</td></tr> <tr><td>SN</td><td>Snow</td><td>Motor icing, visibility; heavy score penalty</td></tr> <tr><td>FG</td><td>Fog</td><td>Visibility below 3SM; likely illegal</td></tr> <tr><td>BR</td><td>Mist</td><td>Visibility 5/8–6SM; check exact value</td></tr> <tr><td>HZ</td><td>Haze</td><td>Reduced visibility; moderate concern</td></tr> <tr><td>-RA</td><td>Light rain</td><td>Caution; watch trend</td></tr> <tr><td>+RA</td><td>Heavy rain</td><td>NO_GO conditions</td></tr> </tbody> </table> <h2>Putting It All Together for a Pre-Flight Decision</h2> <p> When you evaluate a METAR before a drone flight, work through these five questions in order: </p> <ol> <li><strong>How old is it?</strong> If conditions are changing, a 55-minute-old METAR may not reflect reality.</li> <li><strong>Are visibility and ceiling legal?</strong> 3SM minimum, 500 ft below the lowest BKN or OVC layer.</li> <li><strong>What is the wind — and especially the gusts?</strong> Compare gust speed to your drone's rated maximum.</li> <li><strong>Is there active weather (TS, RA, SN, FG)?</strong> Any of these warrant a hold or cancel.</li> <li><strong>Is the temperature/dewpoint spread closing fast?</strong> If a trend METAR (TAF) or TREND group shows a tightening spread, fog formation is imminent.</li> </ol> <p> DroneSkycast automates this evaluation with a 0–100 score, but understanding the raw data lets you challenge the verdict when local topography or rapidly changing conditions make the nearest METAR station unrepresentative. Check the full scoring breakdown in our <a href="https://droneskycast.com/learn/part-107-weather-requirements">Part 107 weather requirements guide</a> and see how METAR data maps to go/no-go decisions. </p> <p> For guidance on how airspace notices interact with your weather decision, read <a href="https://droneskycast.com/learn/tfrs-notams-sigmets">TFRs vs NOTAMs vs SIGMETs for Drone Pilots</a>. </p>