s_metar 1.0.2

Parse/decode METAR/TAF aeronautical weather reports (wind, visibility, weather, clouds...). Fetch live/past METAR/TAF data from aviationweather.gov API.

s_metar

A Flutter/Dart package for parsing METAR and TAF aeronautical weather reports from aviation meteorological stations worldwide + and also provides a fetch static method to get METAR and TAF from aviationweather.gov API

Features

METAR parsing

• Wind — direction (degrees, cardinal, variable), speed & gusts in kt/m/s/km/h/mph, Beaufort scale, isCalm flag
• Visibility — prevailing and minimum visibility in all units; isMaximum flag for 9999 (≥10 km); CAVOK detection
• Weather — intensity, descriptor, precipitation (including compound codes like RASN, FZRASN), obscuration, other phenomena
• Clouds — cover (raw ICAO code + translation), height in ft/m/km, oktas, cloud type (CB, TCU)
• Temperatures — temperature & dewpoint with relative humidity, dewpoint spread, heat index (NOAA), wind chill
• Pressure — altimeter/QNH in hPa/inHg/mbar/bar/Pa/kPa/atm
• Runway Visual Range (RVR) — up to 3 runway ranges with trend
• Recent weather, windshear, sea state, runway state
• Weather trends — TEMPO/BECMG trend groups
• Flight rules — VLIFR / LIFR / IFR / MVFR / VFR derived automatically
• shouldBeCavok() — analyses current conditions to determine if CAVOK applies

TAF parsing

• Valid period, AMD/COR modifier, NIL/CANCELLED
• Wind, visibility, weather and clouds as above
• Max/min temperature forecasts
• Change periods: FM, TEMPO, BECMG, PROB30, PROB40

Live METAR/TAF fetching

• Added MetarTafFetcher class for fetching live weather data from aviationweather.gov API
• Added MetarTafResult class for typed fetch results with parsed Metar/Taf objects and raw data
• ICAO code validation: ensures 4-character codes (first char letter, rest alphanumeric) via isValidIcao()
• DateTime validation: rejects future dates and returns descriptive error
• Integration with s_client API for HTTP requests with automatic retry and error handling
• CORS proxy support for web builds:
  • proxyUrls static list for configurable proxy URLs (default: two Cloudflare Workers for redundancy)
  • customProxyUrls parameter on fetch() for per-request proxy override
  • Automatic proxy fallback: tries each proxy in order, switches on rate limit (429/503 status codes)
  • Direct API fallback when all proxies fail
• Deployment resources:
  • Cloudflare Worker implementation in lib/s_metar/deployment/cloudflare-worker.js
  • Vercel Edge Function implementation in lib/s_metar/deployment/vercel-edge-function.js
  • Comprehensive deployment guide in lib/s_metar/deployment/README.md
  • Usage examples in lib/s_metar/deployment/USAGE_EXAMPLES.dart

Example app integration

• Added interactive s_metar example screen with 3-tab interface:
  • METAR tab: preset samples (EGLL, KJFK, Winter, CAVOK) + custom input with live parsing
  • TAF tab: editable TAF code with live parsing
  • Live Fetch tab: ICAO input, date/time picker, and real-time API fetching
• Expandable cards showing parsed weather data (wind, visibility, clouds, temperatures, pressure)
• Registered in package examples registry under "Networking" category

Installation

dependencies:
  s_metar: ^1.0.2

Quick start

Basic usage

import 'package:s_metar/s_metar.dart';

// Parse a METAR
final metar = Metar('METAR EGLL 181220Z 25015G28KT 220V280 9999 FEW020 BKN080 15/08 Q1012 NOSIG');

print(metar.wind.speedInKnot);          // 15.0
print(metar.wind.gustInKnot);           // 28.0
print(metar.wind.beaufort);             // 6
print(metar.temperatures.relativeHumidity);  // ~62 %
print(metar.pressure.inHPa);           // 1012.0
print(metar.flightRules);              // 'VFR'

// Parse a TAF
final taf = Taf('TAF EGLL 181100Z 1812/1918 25015KT 9999 FEW025 '
    'TEMPO 1812/1816 5000 RASN BKN012 '
    'BECMG 1901/1903 30008KT');

print(taf.valid.periodFrom);
print(taf.changesForecasted.length);   // 2

Advanced usage

import 'package:s_metar/s_metar.dart';

// --- Derived temperature quantities ---
final metar = Metar('METAR EGLL 181220Z 25015G28KT 220V280 9999 FEW020 BKN080 15/08 Q1012 NOSIG');
final t = metar.temperatures;

print(t.dewpointSpread);               // 7.0 °C  (< 3 → fog risk warning)
print(t.relativeHumidity);             // ~62 %
print(t.heatIndex);                    // null (only applicable above 27 °C)
print(t.windChill(metar.wind.speedInKph)); // wind-chill in °C

// --- Compound precipitation codes ---
final winter = Metar('METAR EGLL 181220Z 05010KT 2500 -RASN BKN008 OVC015 03/01 Q0992');
for (final w in winter.weathers.items) {
  print(w.code);                       // '-RASN'
  print(w.precipitationCodes);         // ['RA', 'SN']
}

// --- Cloud ceiling & CAVOK ---
print(metar.clouds.ceiling);           // false (no BKN/OVC ≤ 1500 ft)
print(metar.prevailingVisibility.cavok); // false
print(metar.shouldBeCavok());          // true/false – auto-analysed

// --- US altimeter (inHg) ---
final us = Metar('METAR KJFK 181220Z 27010KT 10SM FEW020 BKN100 18/10 A2992');
print(us.pressure.inInHg);             // 29.92
print(us.pressure.inHPa);             // ~1013.2

// --- TAF change periods ---
final taf = Taf(
  'TAF EGLL 181100Z 1812/1918 25015KT 9999 FEW025 '
  'TEMPO 1812/1816 5000 RASN BKN012 '
  'BECMG 1901/1903 30008KT '
  'PROB40 TEMPO 1906/1910 3000 DZ BKN006',
);

for (final cp in taf.changesForecasted.items) {
  print(cp.changeIndicator.code);      // TEMPO / BECMG / PROB40 TEMPO
  print(cp.flightRules);              // IFR / MVFR / VFR …
}

// --- Live fetch (requires network) ---
final result = await MetarTafFetcher.fetch(
  icao: 'EGLL',
  dateTime: DateTime.now().toUtc(),
);

if (result.isSuccess) {
  print(result.rawMetar);             // raw METAR string
  print(result.metar?.flightRules);   // parsed flight rules
  print(result.taf?.changesForecasted.length);
}

Example app

See the example/ directory for a full interactive demo — pick from preset METARs, enter your own code, browse every parsed field, and fetch live reports by ICAO code.

cd example
flutter run

License

MIT — see the LICENSE file.

Repository

https://github.com/SoundSliced/s_metar