Weather

Barovia's weather (F12, story/weather.gd): what each kind does, how often each climate has it (weights for each six-hour spell), which regions have which climate, and how Strahd's attention brings more storms. The lake country (Vallaki, the lake, Van Richten's tower) rains more, Berez is foggier and the Wizard of Wines wetter (the vault's Region Variety Plan).

WeatherTravel speedRoad danger (day/night)Hides things
Overcast×1.0+0.0 / +0.0
Fog×1.0+0.05 / +0.05yes
Rain×1.0+0.0 / +0.0
Storm×1.25+0.0 / +0.05yes
Snow×1.25+0.0 / +0.0
Blizzard×2.0+0.0 / +0.0yes

Climates

How likely each kind of weather is in each climate (it changes every six hours), and where each climate holds. Everywhere not listed is valley.

ClimateOvercastFogRainStormSnowBlizzardRegions
Valley36%27%27%9%everywhere else
Lakeland27%27%36%9%Vallaki, Lake Zarovich, Van Richten's Tower
Marsh27%45%18%9%Berez
Vineyard27%18%45%9%The Wizard of Wines
Highland36%18%9%9%27%Krezk, The Abbey of St. Markovia
Mountain20%20%40%20%The Tsolenka Pass, Mount Ghakis, Mount Baratok, The Amber Temple
Castle9%18%27%45%Castle Ravenloft