Speaking as a Californian who has lived near the coast before, if Vista city is approx the equivalent of Crescent City, CA then there will be no snow.
You can expect fog in the morning- the colder the longer it hangs around. Many winter days end up overcast unless the wind blows the clouds away. Winter is a rainy season rather than snowy. Most showers are light with the clouds rolling through pretty fast on the ocean breeze but occasionally there are hard showers. (Not as common as inland.) If there's going to be a winter storm that close to the ocean, you'd hear warnings on the news so people don't go out swimming. XD The water would be super cold so if anyone goes swimming purposely they either have a wet suit on or they're experienced swimming in really cold waters. (Even in the summer wet suits are common place. The Pacific is colder than the Atlantic and feels nothing like Hawaii beaches unless you're in Southern California.) So come up with a clever reason if you want to throw someone in the water. Maybe your character loves taking cold showers?
The temperature can change dramatically within the same day. Sometimes it feels really cold- down in the upper 30s at night. Not below freezing though. Again, no snow. When I lived out near the shore, there were abnormal days where the sun would come out in the middle of the day and it would be nice. The weather seems to change quickly there on the coast. On average in Crescent City it goes up to a high of 53 F and low of 39 F.
CA coast weather
You can expect fog in the morning- the colder the longer it hangs around. Many winter days end up overcast unless the wind blows the clouds away. Winter is a rainy season rather than snowy. Most showers are light with the clouds rolling through pretty fast on the ocean breeze but occasionally there are hard showers. (Not as common as inland.) If there's going to be a winter storm that close to the ocean, you'd hear warnings on the news so people don't go out swimming. XD The water would be super cold so if anyone goes swimming purposely they either have a wet suit on or they're experienced swimming in really cold waters. (Even in the summer wet suits are common place. The Pacific is colder than the Atlantic and feels nothing like Hawaii beaches unless you're in Southern California.) So come up with a clever reason if you want to throw someone in the water. Maybe your character loves taking cold showers?
The temperature can change dramatically within the same day. Sometimes it feels really cold- down in the upper 30s at night. Not below freezing though. Again, no snow. When I lived out near the shore, there were abnormal days where the sun would come out in the middle of the day and it would be nice. The weather seems to change quickly there on the coast. On average in Crescent City it goes up to a high of 53 F and low of 39 F.
Hope that helps!