The best times to visit Castro Valley for ideal weather are
April 23rd to November 11th
based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.
Castro Valley Travel Guide
Other Castro Valley Travel Info
Weather in Castro Valley
Average temperatures in Castro Valley vary greatly. Considering humidity, temperatures feel nice most of the year, excluding some cold weeks in the winter, with a very low chance of rain or snow throughout the year. The area is more temperate than most — in the 65th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Castro Valley, the hottest months are September, August, and then July. See average monthly temperatures below. The warmest time of year is generally late August to early September where highs are regularly around 86°F (30°C) with temperatures rarely dropping below 60.2°F (15.7°C) at night.
Castro Valley Temperatures (Fahrenheit)
Castro Valley Temperatures (Celsius)
The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.
Castro Valley Perceived Temperature (F)
Castro Valley Perceived Temperature (C)
Average Castro Valley Temperatures by Month
Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.
|Month||Avg. High (°F)||Avg. Mean (°F)||Avg. Low (°F)|
|Month||Avg. High (°C)||Avg. Mean (°C)||Avg. Low (°C)|
Precipitation (Rain or Snow)
If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Castro Valley are June, July, and then August. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around late May. For example, on the week of May 21st there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in late January with an average of 3 days of significant precipitation the week of January 22nd.
When can you find snow in Castro Valley? Weather stations report no annual snow. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.
Chance of Precipitation
The graph below shows the % chance of rainy and snowy days in Castro Valley.
Snow on the Ground
The graph below shows the average snow on the ground in Castro Valley (in).
Average Rain and Snow by Month
|Month||Daily Chance of Rain||Average Snow Depth (in)||Total Precipitation (in)|
|Month||Daily Chance of Rain||Average Snow Depth (cm)||Total Precipitation (cm)|
Humidity and Wind
Castro Valley has some high humidity months, with other comfortably humid months. The least humid month is October (56.7% relative humidity), and the most humid month is February (68.3%).
Wind in Castro Valley is usually calm. The windiest month is April, followed by June and May. April’s average wind speed of around 7.2 knots (8.3 MPH or 13.4 KPH) is considered “a gentle breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in early to mid April where average top sustained speeds reach 16.3 knots, which is considered a moderate breeze.
Relative Humidity (%)
The graph below shows the average % humidity by month in Castro Valley.
The graph below shows wind speed (max and average) in knots.
Average Wind Speeds
Show Wind Speeds
All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.
|Month||Avg. Wind||Avg. Wind Feel||Sustained High Wind||High Wind Feel|
|Jan||4.7||Light breeze||10.7||Gentle breeze|
|Feb||5.2||Light breeze||11.8||Significant breeze|
|Mar||5.7||Light breeze||13.2||Gentle breeze|
|Apr||7.2||Gentle breeze||15.4||Significant breeze|
|May||7||Gentle breeze||14.5||Gentle breeze|
|Jun||7||Gentle breeze||14.1||Significant breeze|
|Jul||7||Gentle breeze||13.5||Gentle breeze|
|Aug||6.3||Light breeze||13.1||Significant breeze|
|Sep||5.4||Light breeze||12.9||Gentle breeze|
|Oct||5||Light breeze||12||Significant breeze|
|Nov||3.5||Barely noticeable||9.5||Gentle breeze|
|Dec||4.5||Light breeze||10.5||Gentle breeze|
Show Relative Humidity by Month
|Month||Avg. Relative Humidity|
Is it Safe to Travel to Castro Valley?
Our best data indicates this area is generally safe. As of Oct 07, 2019 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Sep 23, 2019.
The Busiest and Least Crowded Months
The busiest month for tourism in Castro Valley, CA, US is July, followed by June and December. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Castro Valley in November. Those willing to visit at these times will likely find it the least expensive month.
Estimated Tourism by Month
Most Popular Months to Visit
Overall Castro Valley Travel Experience by Season
Spring (March through May)
Humidity and temperatures combine to make this season feel moderate. Highs range from 72.2°F (22.3°C) and 62.2°F (16.8°C) with warmer temperatures in the later months. Rain is rare with 1 to 4 days of significant precipitation per month. Spring is the slowest for tourism, which makes it a good time for those looking for deals.
Summer (June through August)
The middle-year months have comfortably cool weather with high temperatures that are comfortable. These months see the least precipitation with about 0 days of precipitation per month. June – August is the busiest season for tourism in Castro Valley, so lodging and other accommodations may cost more than usual.
Fall (September through November)
Fall daily highs range from 79.5°F (26.4°C) and 63.6°F (17.6°C), which will feel comfortable given the humidity and wind. It rains or snows a normal amount: 1 to 2 days per month. Tourism is fairly slow during these months due to the weather, so hotels may be lower priced.
Winter (December through February)
Weather is too cold this time of year in Castro Valley to be enjoyable for warm weather travelers. The average high during this season is between 62.2°F (16.8°C) and 54.4°F (12.4°C). On average, it rains or snows a fair amount: 7 to 9 times per month. These times of year are the second busiest with tourists.