Cool
Average highs are around 14°C, so pack for cooler days.
December verdict
Napa, California, United States in December
Weather score22Poor
Poor for holiday weather
Average highs are around 14°C, so pack for cooler days. Sunshine averages 4.9h per day, so this is not one of the brighter months. Rainfall averages 145mm, so some wet days are possible.
December weather
Monthly averages
Temp
14°C
Rain
145mm
Sun
4.9h
Sea
12°C
Weather score
22
Poor
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
SwimSwim
Weather scoreWeather score
Trip feel
Showers
Rainfall averages 145mm, so some wet days are possible.
Limited sun
Sunshine averages 4.9h per day, so this is not one of the brighter months.
Cool sea
Sea temperatures average 12°C, so the water can feel cool.
Map
Weather map
Compare Napa, California, United States with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
December14°C average high
December has some of the coolest average daytime highs of the year, so pack for fresher conditions.
Warmest monthsJune to September
This stretch sets the upper range for average daytime heat.
Rain
December145mm average rain
December is wetter than Napa's yearly average, so flexible plans matter more.
Driest monthsApril to October
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
December4.9 hours average sun
December is one of Napa's cloudier months, so sunshine-led plans are less reliable.
Brightest monthsApril to August
This stretch has the strongest sunshine in the monthly averages.
Sea temperature
December12°C average sea
December is close to Napa's yearly sea-temperature average, so swimming comfort is fairly typical.
Warmest seaJanuary and August to December
Sea temperatures are usually near 12°C in this stretch, so swimming comfort is at its strongest.
Weather score
December22 weather score
December is one of the weakest weather-score months, when the overall mix is less favourable than the rest of the year.
Best weather monthsMay to September
These months have the strongest weather score in the monthly averages.
