Weather in Barovia

2: GeistSturm
3: Driving Rain
4: Heavy rain
5: heavy fog
6: light rain
7: Fog
8: light fog
9: Overcast
10: windy
11: light fog
12: clear

Overcast
No bright sunlight is visible, all naturally lit areas are lit only by dim light, and a vague sense of disquiet or malaise is felt by all. This effect is present for all weather conditions except for clear.

GeistSturm
All outdoors living being that are not sworn to Strahd have disasvantage on all dicerolls. On a result of double 1's, 1d4+1 Wraiths appear to attack the unfortunate victim. When this occurs, all previous effects ends. The day is then windy.

Driving Rain
Visibility is reduced to 45 feet, dexterity saves have disadvantage while outdoors, and creatures have resistance to fire damage. If ignited, open flames are extinguished the following turn. Dirt becomes difficult terrain, and dashing on stone requires a dexterity save dc14 or the running creature falls prone. Survival and Perception checks have disadvantage and -5.

Heavy rain
Visibility is reduced to 90 feet, creatures have resistance to the first instance of fire damage they take each round, and open flames are extinguished. Creatures have advantage on checks to put out fires, or may do so as a bonus action, or both. Dirt becomes difficult terrain. Survival and Perception Checks have disadvantage.

Heavy fog
Visibility is reduced to 10 feet, bright light reduces visibility to 5 feet, and creatures have advantage on perception checks to spot bright and dim light.

Light rain
Visibility reduced to 200 feet, open flames are extinguished if they are smaller than a 5 foot area or is on the ground. Saves against fire damage have advantage, and plants have regeneration for 3 hitpoints at the start of their turn when alive. Survival checks have disadvantage.

Fog
Visibility is reduced to 45 feet, bright light reduces visibility to 30 feet, and creatures have advantage on perception to spot bright lights.

Light fog
Visibility is reduced to 90 feet.

Windy
A strong wind blows. Uncovered flames smaller than a campfire are extinguished, and unsecured objects begin to move from the wind. Survival checks to track by scent have advantage or disadvantage, depending on the wind's direction. Wind direction is re-selected every 6 hours.
1: North
2: South
3: West
4: East

Clear
There are no clouds in the sky; the sun is warm and bright, the flowers bloom, and evil flees to the shadows. All living things that oppose Strahd gain a +1 to Intelligence, Wisdom, and Charisma saves, and reroll 1s on all checks.