Weather system

Weather in radarcontrol.io affects aircraft operations and forces you to make real decisions - rerouting traffic, approving deviations, choosing runways based on wind.

Real-time METAR (Tower mode)

In Tower mode, airports display real-time weather observations (METAR) fetched from aviation weather services. The METAR panel shows:

• Wind - Direction and speed (used for automatic runway selection)
• Visibility - Current visibility conditions
• Ceiling - Cloud coverage and base altitudes
• Flight category - VFR, MVFR, IFR, or LIFR

Simulated vs real weather

When METAR is available, wind data from the observation is used for runway selection. However, the visual weather simulation (cells, precipitation overlays) does not reflect the real METAR - it follows the weather intensity slider. This means you may see departures using a wind-appropriate runway while the simulated radar overlay shows different conditions.

METAR updates

METAR data is cached and refreshes approximately every 15 minutes. If no METAR is available for an airport, the simulation falls back to generated wind conditions.

Weather intensity

Use the Weather slider in the control panel (right side) to adjust weather conditions from calm to severe:

• 0% - Clear skies, no weather cells, light winds
• 25% - Light weather, occasional small cells
• 50% - Moderate weather, multiple cells, stronger winds
• 75% - Heavy weather, larger cells, significant wind
• 100% - Severe weather, large intense cells, strong winds

Weather overlays

Weather radar

Toggle the Radar overlay checkbox to display convective weather cells on the radar scope. Cells are rendered with a pixelated appearance similar to real ATC radar displays.

Use the Opacity slider (0-50%) to adjust the transparency of the weather overlay. Lower values make the weather more transparent so aircraft and waypoints remain clearly visible.

Color coding by intensity:

• Green - Light precipitation
• Yellow - Moderate precipitation
• Red - Heavy precipitation
• Magenta - Extreme/severe weather

Cells grow, mature, and dissipate over time. They drift with upper-level winds, typically moving 15-60 knots depending on conditions.

Wind barbs

Toggle the Wind barbs checkbox to display standard meteorological wind barbs across the radar scope. Use the altitude selector to view winds at different flight levels:

• SFC - Surface wind
• FL100 - 10,000 feet
• FL200 - 20,000 feet
• FL300 - 30,000 feet
• FL400 - 40,000 feet

Reading wind barbs:

• The barb points in the direction the wind is coming FROM
• Half barb = 5 knots
• Full barb = 10 knots
• Pennant (triangle) = 50 knots

Wind effects on operations

Runway selection

When weather is active, departing aircraft automatically use runways aligned with the surface wind direction. Aircraft take off into the wind, so runway heading will match the wind direction.

Example: With wind from 270° (westerly), departures will use runway 27.

Wind layers

Wind varies with altitude:

• Surface winds are lightest
• Winds increase with altitude
• Direction veers (shifts clockwise) with height
• Upper-level winds can be significantly stronger

Deviation requests

When aircraft detect weather cells in their flight path, they will request deviations to avoid the weather.

Deviation request panel

When an aircraft requests a deviation, a panel appears showing:

• Callsign - Aircraft requesting deviation
• Direction - LEFT or RIGHT with distance (e.g., "LEFT 15nm")
• Reason - Description of the weather threat

Controller actions

• Approve - Aircraft turns 30° in the requested direction and the heading vector shows on radar
• Deny - Aircraft maintains current route

CRITICAL

Denying a deviation request risks losing the aircraft. If you deny a deviation and the aircraft flies into severe weather, it may be lost. A crash screen will appear showing the incident. Weather deviations exist for safety and should almost always be approved.

Radio calls

When a deviation request is generated:

1. Pilot request appears in the radio banner: "DYNASTY 828, request left deviation two zero miles for weather"
2. When approved, ATC clearance followed by pilot readback: "DYNASTY 828, deviation approved, left of course approved"
3. If denied, ATC denial followed by pilot acknowledgment: "DYNASTY 828, unable deviation, maintain present course"

TIP

Deviation requests auto-approve after 60 seconds if not handled. In real ATC, pilots have authority to deviate for weather safety.

Scripting API

Weather data is available through the scripting API for custom scenarios.

Querying weather

// Get wind at specific altitude
const wind = weather.windAt(35000);
console.log(`FL350: ${wind.dirDeg}° at ${wind.kts} knots`);

// Get surface wind
const surface = weather.surfaceWind();
console.log(`Surface: ${surface.dirDeg}° at ${surface.kts} knots`);

// Get all weather cells
const cells = weather.cells();
for (const cell of cells) {
  console.log(`Cell at ${cell.center.lat}, ${cell.center.lon}`);
  console.log(`  Radius: ${cell.radiusNm}nm, Intensity: ${cell.intensity}`);
}

// Get current intensity setting
const intensity = weather.intensity();

Deviation request event

// Handle deviation requests in script
onDeviationRequest((request) => {
  console.log(`${request.callsign} requesting ${request.direction} deviation`);
  console.log(`Reason: ${request.reason}`);

  // Return true to approve, false to deny, undefined to leave pending
  return true; // Auto-approve all deviations
});

Request properties

Property	Type	Description
id	string	Unique request identifier
callsign	string	Aircraft callsign
direction	'left' | 'right'	Requested deviation direction
deviationNm	number	Requested deviation distance in nm
reason	string	Human-readable reason
weatherCellId	string	ID of the threatening weather cell

Tips

• Keep weather radar on so you see cells before your pilots do
• Route aircraft around weather proactively - don't wait for deviation requests
• Weather cells have vertical limits. Sometimes climbing above is easier than going around.
• Approve deviations fast. Delays mean aircraft fly closer to the weather.
• More weather = more deviations = more spacing needed