For immersion, I think it would be great for NPCs to react to the weather by covering their heads and running for shelter or by pulling out an umbrella. Make this randomized so it doesn't look like the same characters are doing the same thing. You can even have NPCs say something whenever the weather changes.
#Make NPCs react to the weather
onyx plinth
unkempt eagle
Random Umbrella Texture nor Model is a must. Pink & Transparent Umbrella is a must 