setOvercast

Notes from before the conversion:

Use setRain if you want to make sure it rains.

Only one script command induced weather change (either setOvercast or setFog) can be happening at a time. Starting a new weather change will immediately halt the current weather change. SetRain changes are independent and can occur simultaneously to a weather change.

Arma 3's volumetric clouds cannot be instantly changed (it would take up to a few seconds to do a full recompute). Therefore, 0 setOvercast 0 will not have the desired effect. You can use skipTime to get to the desired cloud coverage.

NOTE: To get instant, seamless overcast change to overcast 1 advance the time 24 hours with skipTime while setting overcast transition time to 86400 seconds (24 hours) - Killzone_Kid (12:08, 15 August 2013)

86400 setOvercast 1;
skipTime 24;

// to remain on the same date:
skipTime -24;
86400 setOvercast 1;
skipTime 24;

With removal of simulSetHumidity, in order to add instant cloud cover, execute simulWeatherSync with delay (for now):

skipTime -24;
86400 setOvercast 1;
skipTime 24;
0 spawn {
    sleep 0.1;
    simulWeatherSync;
};

There is slight freeze with simul command.

Delay in Arma 3 doesn't work for quick changes. Using 120 setOvercast 1 only reaches full overcast after about 50 minutes. Using setTimeMultiplier does speed up the overcast, but it doesn't render any clouds. You will need to skipTime or forceWeatherChange to render clouds if you want it to happen within the hour.

Actual transition time is inversely proportional to the timeMultiplier. For example, a time of 7200 (2 hours) and a timeMultiplier of 2 will result in a real-life transition time of 7200 / 2 = 3600 (1 hour).

In case of overcast, a timeMultiplier > 1 will cause gradual desyncing of the cloud cover with the overcast value, so it is advised that you multiply the transition time by the multiplier, i.e. :

(7200 * timeMultiplier) setOvercast 1