Weather Parameters

This guide covers every parameter you can use in rules, the tier that unlocks it, and how it helps you target specific photography conditions. All parameter names are snake_case and match the API exactly.

Weather Data Updates

• Cadence: Free updates every 6 hours. Pro updates hourly.
• Forecast Range: 3 days (Free), 14 days (Pro)
• Core Variables: Free includes 16 surface variables plus 5 computed parameters (21 total). Pro includes 24 surface variables plus the same 5 computed parameters (29 total).
• Advanced Layers (Pro): Ensemble clouds, atmospheric aerosols, upper air dynamics, and marine wave forecasts.

Core Weather Parameters (BASE)

Temperature and Heat

temperature_2m (Free)

• Unit: °C
• Range: -50.0 to 60.0
• Description: Air temperature at 2 meters above ground
• Photography Use: Comfortable shooting range 15-25°C. Cold enhances frost/fog, warmth creates haze.

apparent_temperature (All tiers, computed)

• Unit: °C
• Range: -60.0 to 70.0
• Description: Temperature accounting for wind chill and humidity
• Photography Use: Important for outdoor comfort during long shoots. Consider wind chill in winter.

soil_temperature_0cm (Free)

• Unit: °C
• Range: -50.0 to 60.0
• Description: Ground/surface temperature at 0cm depth
• Photography Use: Surface temperature determines frost formation. Often 2-4°C cooler than air temperature.

freezing_level_height (Pro)

• Unit: m
• Range: 0 to 8000
• Description: Height of 0°C isotherm above sea level
• Photography Use: Key for mountain work—tells you where snow vs rain will occur.

snow_depth (Pro)

• Unit: m
• Range: 0 to 10
• Description: Snow depth accumulated on ground
• Photography Use: Fresh snow creates dramatic winter landscapes and clean backgrounds.

Humidity and Moisture

relative_humidity_2m (Free)

• Unit: %
• Range: 0 to 100
• Description: Moisture content relative to saturation
• Photography Use: High humidity (>80%) increases fog chances. Low humidity creates clear air.

dew_point_2m (All tiers, computed)

• Unit: °C
• Range: -50.0 to 40.0
• Description: Dew point temperature at 2 meters
• Photography Use: Close to air temperature creates fog conditions. Important for frost prediction.

dewpoint_spread_c (All tiers, computed)

• Unit: °C
• Range: 0.0 to 30.0
• Description: Temperature difference between air temperature and dew point
• Photography Use: Low values (0-3°C) indicate high fog probability. Perfect for atmospheric photography.

vapour_pressure_deficit (All tiers, computed)

• Unit: kPa
• Range: 0 to 7
• Description: Difference between saturation and actual vapor pressure
• Photography Use: Low values indicate humid conditions. High values suggest dry air and potential haze.

cloud_base_height (All tiers, computed)

• Unit: m
• Range: 0 to 10000
• Description: Estimated cloud base height above ground
• Photography Use: Low bases (<300m) create fog/mist; mid bases catch golden light; high bases deliver dramatic skies.

Cloud Coverage

cloud_cover (Free)

• Unit: %
• Range: 0 to 100
• Description: Overall cloud coverage across all altitudes
• Photography Use: Partial clouds (20-80%) create dramatic lighting. Clear for stars, overcast for even light.

cloud_cover_low (Free)

• Unit: %
• Range: 0 to 100
• Description: Cloud coverage below 2km altitude
• Photography Use: Low clouds create atmospheric layers and fog effects.

cloud_cover_mid (Free)

• Unit: %
• Range: 0 to 100
• Description: Cloud coverage between 2-6km altitude
• Photography Use: Mid-level clouds create textures without blocking golden hour light.

cloud_cover_high (Free)

• Unit: %
• Range: 0 to 100
• Description: Cloud coverage above 6km altitude (cirrus)
• Photography Use: Thin high clouds enhance sunsets without blocking light completely.

Wind Conditions

wind_speed_10m (Free)

• Unit: m/s
• Range: 0 to 50
• Description: Wind speed at 10 meters above ground
• Photography Use: Low wind for sharp images. Moderate wind creates motion in clouds/water.

wind_direction_10m (Free)

• Unit: ° (degrees)
• Range: 0 to 360
• Description: Wind direction in degrees (0° = North)
• Photography Use: Wind direction affects cloud movement and wave patterns.

wind_gusts_10m (Free)

• Unit: m/s
• Range: 0 to 80
• Description: Maximum wind gust speed
• Photography Use: Strong gusts can shake tripods. Plan for wind protection.

Precipitation

precipitation (Free)

• Unit: mm
• Range: 0 to 300
• Description: Combined rain and snow precipitation
• Photography Use: Light precipitation creates atmosphere. Protect gear above 1mm/h.

rain (Free)

• Unit: mm
• Range: 0 to 300
• Description: Liquid precipitation amount
• Photography Use: Light rain creates reflections. Moderate rain requires weather protection.

showers (Pro)

• Unit: mm
• Range: 0 to 100
• Description: Shower-type precipitation (brief, heavy bursts)
• Photography Use: Showers create dramatic lighting with sun breaks and rainbows.

snowfall (Free)

• Unit: mm
• Range: 0 to 1000
• Description: Snow precipitation amount
• Photography Use: Fresh snow transforms landscapes. Light snowfall creates magical atmosphere.

precipitation_probability (Free)

• Unit: %
• Range: 0 to 100
• Description: Probability of any precipitation occurring
• Photography Use: Below 30% is safe. 50-70% can create dramatic skies if prepared.

Light and Solar Radiation

sunshine_duration (Free)

• Unit: seconds
• Range: 0 to 3600
• Description: Seconds of direct sunlight per hour
• Photography Use: Long duration creates strong shadows. Limited duration offers softer conditions.

shortwave_radiation (Pro)

• Unit: W/m²
• Range: 0 to 1500
• Description: Shortwave solar radiation from sun
• Photography Use: Total solar radiation available for photography lighting.

uv_index (Pro)

• Unit: UV index
• Range: 0 to 15
• Description: UV radiation index (0-15+)
• Photography Use: High UV creates harsh lighting but clear skies. Protect equipment and skin.

Atmospheric Conditions

visibility (Free)

• Unit: m (meters)
• Range: 0 to 50000
• Description: Horizontal visibility distance
• Photography Use: Reduced visibility (<5km) creates atmosphere. Clear visibility (>20km) for distant subjects.

surface_pressure (Pro)

• Unit: hPa
• Range: 870 to 1085
• Description: Atmospheric pressure at surface level
• Photography Use: High pressure (>1020 hPa) brings clear skies. Low pressure creates dynamic weather.

Aurora Inputs

aurora_kp_predicted (Free)

• Unit: Kp index
• Range: 0.0 to 10.0
• Description: Predicted geomagnetic activity
• Photography Use: Higher Kp values indicate stronger geomagnetic storms and better aurora visibility.

aurora_activity (Free)

• Unit: %
• Range: 0.0 to 100.0
• Description: Location-adjusted aurora activity score
• Photography Use: Scores above 70% are excellent; still combine with cloud/solar elevation checks.

Stability and Storm Signals

cape (Pro)

• Unit: J/kg
• Range: 0 to 8000
• Description: Convective Available Potential Energy
• Photography Use: High CAPE (>2500 J/kg) indicates thunderstorm potential - dramatic but dangerous.

lifted_index (Pro)

• Unit: °C
• Range: -15 to 15
• Description: Temperature difference measure for atmospheric stability
• Photography Use: Negative values indicate instability. -6 to -4 creates spectacular storm opportunities.

Advanced Atmospheric Fields (Pro)

Ensemble (Pro) — GEFS cloud consensus:

• ensemble_clear_probability: % (0-100) — Chance of clear sky; great for confidence checks.
• ensemble_cloud_cover_spread: % (0-100) — Cloud forecast volatility; low spread = agreement.

Aerosol (Pro) — CAMS clarity metrics:

• aod_550: Total aerosol optical depth (0-3, dimensionless); lower = clearer air.
• dust_aod_550: Dust component AOD (0-3); warm-toned haze indicator.
• smoke_aod_550: Smoke component AOD (0-3); wildfire/pollution haze detector.
• sea_salt_aod_550: Sea salt AOD (0-3); coastal haze signal.
• angstrom_550_865: Ångström exponent (0-3); particle size clue (high = fine particles).

Dynamics V1 GFS 0.5° (Pro) — Upper-air structure:

• omega_700hpa / omega_500hpa: Pa/s (-10 to 10); negative = rising air, cloud growth.
• wind_shear_0_6km / wind_shear_0_3km: m/s (0-50 / 0-40); organized convection/rotation cues.
• simulated_reflectivity_dbz: dBZ (0-80); model radar proxy for intense cells.
• rh_700hpa / rh_850hpa: % (0-100); mid/low-level moisture for cloud longevity and fog.
• srh_0_3km: m²/s² (0-500); low-level helicity for dramatic storm structure.
• absv_500hpa: s⁻¹ (-0.001 to 0.001); mid-level vorticity for dynamic systems.
• convective_precip_fraction: fraction (0-1); convective share of precip (showery vs stratiform).
• ice_fraction_mid: fraction (0-1); ice content in mid clouds for halos/optics potential.
• tropopause_height_m: m (5000-20000); convective ceiling and anvil character.

Marine GFS Wave (Pro, coastal) — Coastal-only:

• wave_height_m: m (0-30); combined wind + swell height.
• swell_height_m: m (0-30); organized swell height.
• wind_wave_height_m: m (0-30); local wind-wave height (chop).
• wind_wave_period_s: s (1-30); wave spacing—short = choppy, long = organized.
• wind_wave_direction_deg / wave_direction_deg: degrees (0-360); approach angle for composition.

Derived Photography Conditions

Free:

• fog_probability: % — Multi-factor fog likelihood (visibility, dewpoint spread, humidity, wind).
• frost_probability: % — Frost formation likelihood from temp/dewpoint/cloud/wind.
• golden_hour_potential: % — Atmospheric quality for golden hour windows.
• aurora_quality: % — Aurora viewing quality using Kp, clouds, darkness; Pro users get automatic OVATION probability/intensity enrichment when available.

Pro:

• fiery_red_sky_potential: % — Sunrise/sunset red-sky setup using cloud layers, humidity, pressure, wind.
• golden_clouds_potential: % — Cloud formations suitable for golden light.
• cloud_drama_score: % — Dramatic sky score mixing clouds, wind, pressure, humidity.
• storm_intensity: % — Combines precip, wind, pressure, visibility, CAPE.
• rainbow_probability: % — Solar geometry + precip alignment; checks rain opposite the sun and sun-side clearance.

Astronomical and Time-Based Conditions (All tiers)

• golden_hour: Warm light when sun 0° to 6° above horizon (morning/evening/any).
• blue_hour: Deep blue after sunset/before sunrise (sun 4° to 8° below).
• civil_twilight / nautical_twilight / astronomical_twilight: Sun 0-6° / 6-12° / 12-18° below horizon.
• astronomical_night: Darkest period between astronomical dusk and dawn.
• is_daylight: Day, night, or any.
• milky_way_visible: When the Galactic Center or MW band is photographable (core/band).
• solar_elevation / solar_azimuth: ° ( -90 to 90 / 0 to 360 ); control light angle and direction.
• moon_phase: new_moon, waxing/waning crescents, quarters, gibbous, full_moon.
• moon_visibility: visible / not_visible.
• moon_illumination: % (0-100); brightness of the moon disc.
• moon_altitude / moon_azimuth: ° (-90 to 90 / 0 to 360); place the moon in frame.
• milky_way_altitude: ° (-90 to 90); Galactic Center elevation for core shots.

Rule Examples

Fog Photography (Free)

• fog_probability ≥ 70%
• wind_speed_10m under 2 m/s
• visibility under 5 km
• golden_hour or sunrise window

Golden Hour Drama (Free → Pro upgrade adds cloud_drama_score)

• golden_hour window
• cloud_cover between 30-70% (add cloud_drama_score for Pro)
• precipitation_probability under 20%
• calm winds (under 5 m/s)

Astrophotography (Free baseline, Pro adds OVATION enhancement)

• astronomical_night
• moon_illumination under 30%
• cloud_cover under 20%
• visibility over 20 km
• aurora_quality ≥ 65% (Pro users get OVATION-boosted scores automatically)

Next Steps

Ready to use these parameters in your rules? Continue to:

1. Time Windows - Control when rules are active
2. Rule Basics - Learn how to create effective rules
3. Complex Conditions - Combine parameters with advanced logic