Castro Valley Weather in December
With daytime temperatures of 14°C (57°F) and nighttime lows of 5°C (41°F), December in Castro Valley brings moderate temperatures during the day. It is also the wettest month of the year, so pack an umbrella.
Rainfall in Castro Valley in December
This month sees the most rain, so carrying an umbrella will ensure you stay dry. Historically, approximately 13 days this month are expected to have rain, averaging 111 mm (4.4 in). Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.
Temperature in Castro Valley in December
If you're visiting Castro Valley in December, expect highs of 14°C (57°F) and overnight lows around 5°C (41°F). Winter occurs in December. Temperatures can feel cooler in the morning and evening, so layering is often the best approach. With overnight lows of 5°C (41°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets. December is characterized by some of the mildest temperatures of the year.
Sunshine in Castro Valley in December
The month brings about 160 hours of sunlight, offering a comfortable mix of sun and overcast.December in Castro Valley has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Castro Valley's climate page.
Castro Valley Temperature in December
Min Temperature
5°C (41°F)
Max Temperature
14°C (57°F)
Chance of Rain
44%
Precipitation
111 mm (4.4 in)
Rainy days
13 days
Humidity
78% *
Sunshine
160 hours *
Percentage Sunshine
54% *
Best Places in the United States of America in December
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in December →
perfect weather
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tolerable
unpleasant
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What to Wear in Castro Valley in December
The weather can swing between comfortable and chilly in December, so flexibility is key. Pack a variety of tops, at least one warm layer, and both shorts and long pants. This gives you options no matter what the day brings. Expect heavy rainfall, so bring good rain protection and waterproof bags. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.What To Do in Castro Valley in December
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Castro Valley's climate page.
Temperature Rainfall Sunshine Humidity
See the full Castro Valley climate overview or explore weather in the United States of America.
