How to Decode a SMETAR Quickly — Key Fields Explained

Real-World SMETAR Examples: Practice Decoding ExercisesSMETAR (Synthetic/Military METAR) reports are weather observation messages tailored for military aviation, combining standard METAR elements with additional fields or codes used by military weather services. This article provides practical decoding exercises using real-world–style SMETAR examples, explains each component step-by-step, and offers tips for efficient interpretation under operational conditions.

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What you need to know before decoding

Before working through examples, make sure you’re familiar with standard METAR elements:

• ICAO station identifier (four-letter code)
• Date/time group (day of month and UTC time, followed by a “Z”)
• Wind (direction in degrees true and speed in knots; gusts marked with “G”)
• Visibility (in statute miles or meters)
• Runway visual range (RVR) (when applicable)
• Weather phenomena (intensity and type, e.g., -RA, TSRA)
• Sky condition (FEW, SCT, BKN, OVC with cloud base in hundreds of feet)
• Temperature and dew point (in °C)
• Altimeter/QNH (in hectopascals or inches Hg)
• Remarks (RMK) — here military additions often appear

Military SMETARs may include:

• Precipitation types or special codes for obscuration (e.g., FG for fog, BR for mist)
• Tactical weather remarks like SIGMET or MELB references
• Runway contamination codes or braking action reports
• Additional visibility metrics (sector visibilities) or cloud layers important for operations

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Example 1 — Basic SMETAR with variable winds

SMETAR KJFK 041751Z 24012KT 6SM -RA SCT020 BKN040 ⁄₂₁ A2992 RMK SLP132

Step-by-step:

• KJFK — station (John F. Kennedy Intl)
• 041751Z — 4th day, 17:51 UTC
• 24012KT — wind from 240° at 12 kt
• 6SM — visibility 6 statute miles
• -RA — light rain
• SCT020 BKN040 — scattered clouds at 2,000 ft, broken at 4,000 ft
• ⁄₂₁ — temp 23°C, dew point 21°C
• A2992 — altimeter 29.92 inHg
• RMK SLP132 — sea-level pressure 1013.2 hPa

Operational notes: marginal VFR with low ceilings; anticipate reduced braking on wet runways during departures/arrivals.

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Example 2 — SMETAR with gusts, variable wind and runway contamination

SMETAR KEDW 302330Z 18015G28KT 1/2SM R14/1200V1800FT R27/3000FT +TSRA OVC012 ⁄₁₆ Q1008 Rwy12/CLRD/BRK MED

Decode:

• KEDW — Edwards AFB
• 302330Z — 30th day at 23:30 UTC
• 18015G28KT — wind 180° at 15 kt, gusting to 28 kt
• 1/2SM — visibility one half statute mile
• R14/1200V1800FT — RVR for Runway 14 variable between 1,200 and 1,800 ft
• R27/3000FT — RVR for Runway 27 is 3,000 ft
• +TSRA — heavy thunderstorm with rain
• OVC012 — overcast at 1,200 ft
• ⁄₁₆ — 17°C/16°C
• Q1008 — pressure 1008 hPa
• Rwy12/CLRD/BRK MED — runway 12 cleared, braking action medium

Operational notes: severe crosswinds and gusts; restricted visibility and possible microbursts with heavy TS—diversions likely recommended for transport-category aircraft.

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Example 3 — SMETAR with obscurations and sector visibilities

SMETAR LFSB 150540Z 03008KT 6000 1400N FG VV002 08/08 Q1015 RMK SEV REDN

Decode:

• LFSB — base identifier (e.g., Swiss military)
• 150540Z — 15th at 05:40 UTC
• 03008KT — wind 030° at 8 kt
• 6000 — visibility 6,000 m overall
• 1400N — sector visibility north 1,400 m (sector code; SMETAR may include sector visibilities as directional)
• FG — fog
• VV002 — vertical visibility 200 ft (indicates obscured sky)
• 08/08 — temperature and dew point equal at 8°C (saturation)
• Q1015 — pressure 1015 hPa
• RMK SEV REDN — severe reduction (remark noting severe reduction in vis)

Operational notes: ceiling essentially zero; IFR/low-visibility ops only, RVSM and low-level approaches affected.

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Example 4 — SMETAR with military-specific codes and runway braking

SMETAR LTBM 091200Z 21020KT 2000 -SHRA BKN018 ⁄₁₅ Q1002 RAB15/2/80/80

Decode:

• LTBM — station (military)
• 091200Z — 9th day at 12:00 UTC
• 21020KT — wind 210° at 20 kt
• 2000 — visibility 2,000 m
• -SHRA — light showers of rain
• BKN018 — broken clouds at 1,800 ft
• ⁄₁₅ — temp/dew point
• Q1002 — pressure 1002 hPa
• RAB15/2/80/80 — military runway braking code set (example: runway abrasion/braking index; format varies by service)

Operational notes: runway braking may be reduced—check specific military braking interpretation charts before ops.

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Example 5 — SMETAR with icing and SIGMET references

SMETAR KBFI 211100Z 35010KT 10SM SCT040 BKN100 02/M02 A3010 RMK ICE SEV NW-SE CTX SIGMET 04/21

Decode:

• KBFI — Boeing Field, military-adjacent operations
• 211100Z — 21st at 11:00 UTC
• 35010KT — wind 350° at 10 kt
• 10SM — visibility 10 statute miles
• SCT040 BKN100 — scattered at 4,000 ft, broken at 10,000 ft
• 02/M02 — temp +2°C, dew point −2°C (potential icing conditions in clouds)
• A3010 — altimeter 30.10 inHg
• RMK ICE SEV NW-SE CTX SIGMET 04/21 — remark indicating severe icing reported NW to SE, see SIGMET 04/21

Operational notes: icing risk significant within cloud layers and precipitation; anti-ice/de-ice required; follow SIGMET guidance.

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Practical decoding exercises (with answers)

Exercise 1 SMETAR EGXX 071830Z 12006KT 9999 -RA BKN025 ⁄₁₂ Q1018 RMK Rwy08/BRKG POOR

Answer: EGXX — station; 07th 18:30Z; wind 120° 6 kt; visibility 10 km; light rain; broken clouds 2,500 ft; temp 14°C dew 12°C; pressure 1018 hPa; runway 08 braking poor.

Exercise 2 SMETAR XXXX 231200Z VRB03KT 3SM -DZ FEW008 OVC020 09/08 A2980 RMK SECTVIS E-2KM

Answer: Variable wind 3 kt; visibility 3 SM; drizzle; few clouds 800 ft; overcast 2,000 ft; temp 9°C dew 8°C; altimeter 29.80 inHg; sector visibility east 2 km.

Exercise 3 SMETAR YYYY 011000Z 27030G45KT 1SM +TSRA OVC008 ⁄₁₈ Q0995 R27/0500FT

Answer: Wind 270° 30 kt gusting 45; visibility 1 SM; heavy thunderstorm rain; overcast 800 ft; temp 20°C dew 18°C; pressure 995 hPa; RVR Runway 27 = 500 ft.

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Tips for efficient decoding under pressure

• Read in fixed order: station/time → wind → visibility/RVR → weather → sky → temp/dew → pressure → remarks.
• Flag any “RMK” content for operationally critical info (braking, SIGMETs, contamination).
• Use memory aids for cloud cover (FEW < SCT < BKN < OVC).
• When in doubt about military-specific codes, consult the local military weather manual or operations desk.

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If you want, I can convert these exercises into printable flashcards or generate additional SMETARs of varying difficulty.