Implementation:CARLA simulator Carla WeatherParameters

Knowledge Sources	CARLA
Domains	Weather System, RPC Serialization
Last Updated	2026-02-15 05:00 GMT

Overview

WeatherParameters is an RPC-serializable class that defines all environmental weather conditions in the CARLA simulation, including 22 built-in weather presets covering day, night, rain, and dust storm scenarios.

Description

Defined in the carla::rpc namespace across a header (~178 lines) and implementation file (~40 lines), this class provides 14 float parameters controlling the weather:

cloudiness, precipitation, precipitation_deposits: cloud cover and rain
wind_intensity: wind strength
sun_azimuth_angle, sun_altitude_angle: sun position
fog_density, fog_distance, fog_falloff: fog parameters
wetness: ground wetness
scattering_intensity, mie_scattering_scale, rayleigh_scattering_scale: atmospheric scattering
dust_storm: dust storm intensity

The implementation file defines 22 static preset configurations including ClearNoon, CloudyNoon, WetNoon, HardRainNoon, ClearSunset, ClearNight, HardRainNight, DustStorm, and others. Each preset specifies all 14 parameters. The class supports UE4 conversion via FWeatherParameters, equality operators, and MsgPack serialization.

Usage

Use this type to set or query the weather conditions of the simulation, either using built-in presets or custom parameter values.

Code Reference

Source Location

Repository: CARLA
File: LibCarla/source/carla/rpc/WeatherParameters.h
File: LibCarla/source/carla/rpc/WeatherParameters.cpp

Signature

namespace carla {
namespace rpc {

  class WeatherParameters {
  public:
    // 22 built-in presets
    static WeatherParameters Default;
    static WeatherParameters ClearNoon;
    static WeatherParameters CloudyNoon;
    static WeatherParameters HardRainNoon;
    static WeatherParameters ClearNight;
    static WeatherParameters DustStorm;
    // ... and 16 more presets

    WeatherParameters() = default;
    WeatherParameters(float cloudiness, float precipitation, ...);

    float cloudiness = 0.0f;
    float precipitation = 0.0f;
    float precipitation_deposits = 0.0f;
    float wind_intensity = 0.0f;
    float sun_azimuth_angle = 0.0f;
    float sun_altitude_angle = 0.0f;
    float fog_density = 0.0f;
    float fog_distance = 0.0f;
    float fog_falloff = 0.0f;
    float wetness = 0.0f;
    float scattering_intensity = 0.0f;
    float mie_scattering_scale = 0.0f;
    float rayleigh_scattering_scale = 0.0331f;
    float dust_storm = 0.0f;

    bool operator==(const WeatherParameters &rhs) const;
    bool operator!=(const WeatherParameters &rhs) const;

    MSGPACK_DEFINE_ARRAY(...);
  };

} // namespace rpc
} // namespace carla

Import

#include "carla/rpc/WeatherParameters.h"

I/O Contract

Field	Type	Default	Description
cloudiness	`float`	0.0f	Cloud cover percentage (0-100)
precipitation	`float`	0.0f	Rain intensity (0-100)
precipitation_deposits	`float`	0.0f	Puddle/deposit amount (0-100)
wind_intensity	`float`	0.0f	Wind strength (0-100)
sun_azimuth_angle	`float`	0.0f	Sun horizontal angle in degrees
sun_altitude_angle	`float`	0.0f	Sun vertical angle in degrees
fog_density	`float`	0.0f	Fog density
fog_distance	`float`	0.0f	Fog starting distance
fog_falloff	`float`	0.0f	Fog falloff rate
wetness	`float`	0.0f	Ground wetness (0-100)
dust_storm	`float`	0.0f	Dust storm intensity (0-100)

Weather Presets

Preset	Time	Condition	Key Differences
ClearNoon	Day (45 deg)	Clear	Low cloudiness, no precipitation
HardRainNoon	Day (45 deg)	Heavy rain	100% precipitation, high fog
ClearNight	Night (-90 deg)	Clear	High fog density, negative altitude
DustStorm	Day (45 deg)	Dust	100% dust_storm, 100% wind

Usage Examples

#include "carla/rpc/WeatherParameters.h"

// Use a preset
auto weather = carla::rpc::WeatherParameters::ClearNoon;

// Or customize
weather.precipitation = 50.0f;
weather.fog_density = 10.0f;

// Apply weather to the simulation
world->SetWeather(weather);

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