People coming from out of the area to relocate to Silicon Valley might not know what to expect from the weather in the San Jose, Santa Clara County, or Silicon Valley Area. Does this part of California ever rain? How hot is the summer? What is the climate like?
In a nutshell, this is a “sub-tropical” area, or a place that enjoys a mild “Mediterranean climate” that is most heavily influenced by the close proximity of the shoreline and the Pacific Ocean. Temps are mild, we get little rainfall compared to many parts of the country.
More specifically, we usually get about 10-20 inches of rainfall a year (less on the east and more on the west) and enjoy as many as 300 sunny days a year. Winters seldom see many hard freezes (but they can happen).
A typical summer day has highs in the mid to upper eighties but very low humidity – so it feels much cooler. Heat waves and heat inversions can run the temps up to the low to mid 100s in the hottest parts of the valley. Luckily it doesn’t happen much, or stay for long! Once in awhile, a rare storm in summer will bring high humidity and thundershowers, but for the most part, summers are dry. The hottest month is typically August.
The coldest month, usually, is December. A January day will often have a high in the 60s or 50s, depending. A cold day here is when it does not get into the 50s (not too common). By February, though, the worst is usually over and it’s even possible to have freak warm days that hit 80 degrees!
Our weather varies from year to year. Some years we get drought conditions and may require water rationing . Other years we get lots of wet weather from the Pacific – temps are warmer but there’s much too much rain: those are the El Niño years. Most often, though, winters aren’t that bad – evenings can be nippy as temps drop into the 20s on the worst nights in December or January. It will make the news that people should cover their citrus trees so they aren’t damaged by the freezing temps. (more…)
If you are moving to Silicon Valley, whether San Mateo or Santa Clara County, you should know that things are a little different in fall and winter than they are in spring and summer. Here are just a few areas that might not be intuitively obvious to the newcomers.
First, a word on appearance. In Santa Clara County, we have two primary sets of hills – one closer to the Pacific Ocean and Monterey Bay (west side), and one closer to central California (east side). Because our local weather is dominated in very large part by the Pacific Ocean, much of the weather blows in from the coast. A lot of the rain gets dumped in the coastal range, also known as the Santa Cruz Mountains. Less makes it all the way to Los Gatos, less still to downtown San Jose, and a much smaller amount to the east foothills and places such as Alum Rock Park. The coastal range (also called just “the hill” by locals) is green year round as it is full of redwoods and other trees which love the moisture. The east side, though, is more grassy, fewer trees, and gets far less rain. In winter the grasses are a lovely green. With drought or in summer, however, the grass turns brown or pale yellow.
For people coming from the east coast, the hills there are more likely green in summer and brown in winter. Here, though, it is the opposite. We don’t usually get rain in summer, so the grasses die and the hills go brown.
Rain, when we get normal patterns, usually begins in November and comes and goes between then and late April. In a typical year, San Jose gets 15-20″ of rain (Los Gatos more, the Los Gatos Mountains much much more). If we get an El Nino pattern year, temps will be warmer than usual and rain will be much more common than typical. It’s not much fun to have an El Nino year, but right now we desperately need the rain, so folks here are all hoping for it.
Second, a word on roads and travel. Silicon Valley enjoys a sub-tropical climate with mild temperatures and not too much rain, even in a normal year. With very little rain most of the time, our streets and highways can develop a dusty, oily film. Whenever we get rain after a dry spell, those highways and roads can be slicker than you might expect. It’s not that we need a ton of rain for the surfaces to become more slippery, either. A very small amount of precipitation can do the trick, so be careful!
If your destination requires going over “the hill”, be triply careful! Too many people, whether regular commuters or first time adventurers, either tailgate or drive too fast, and it can make it too easy for accidents to happen when a little weather is added into the mix. (more…)
I am frequently contacted by extremely bright, successful engineers or high tech professionals who are in large homes on large lots with great schools in less expensive areas of the country. They want to move here because Silicon Valley is the hub of innovation, our weather’s great, crime’s low and there’s so much to do in this region. They know that housing costs here are extraordinarily high, but they hope that the salaries are commensurately high such that they can replicate the home & lifestyle they currently have – but put it here.
But that really doesn’t work. Unless someone’s relocating here from Boston, New York, Tokyo or Paris (or somewhere equally astronomically priced), the salary offered in Silicon Valley will not usually make that kind of housing duplication possible.
To move here normally means downgrading the house and paying more for it. Yes, incomes are a little higher but not nearly enough to match the discrepancy in real estate prices. I tell people, as a rule of thumb, that when you move here you will pay twice as much and get half as much. (Salaries? You get a little more. Not twice.)
Sometimes I get the comment “I don’t want to move to Silicon Valley and have my family’s lifestyle negatively impacted by having to live in a smaller house. I want the quality of life to go up, not down.”
That is completely understandable. People who move here don’t do it because of housing. Lifestyle often is better here. Shoveling snow? Forgetaboutit. We have 300 sunny days a year on average – if you love to be outdoors, your lifestyle will be far better here where the weather is subtropical. We have the Pacific Ocean an hour or less away, San Francisco an hour away, about 2 dozen wineries, theatre, museums, the Sharks, parks and trails. Our population is highly diverse and highly educated. Crime is low. There are a thousand reasons why the lifestyle here probably is far better than in other parts of the country… but it’s not if you equivocate housing with lifestyle.
A couple of days ago I made a quick trip to Spokane, Washington, on some family business. As I’m writing this in mid-December, just short of the winter solstice (shortest day of the year), I was struck by how early the sun set and then, the following morning, how late it rose again. It seemed like I’d “lost” an hour of daylight.
Upon returning home to the San Jose and Los Gatos area (Silicon Valley), I found an awesome site that charts sunrise and sunset (dawn and dusk) times for all of the world. The link below will take you to the page for San Jose, California, which is a good representation of Santa Clara County and the general Silicon Valley area.
I played with this site awhile, checking the hours of daylight for today going north and south of this area. It will be the same amount of daylight hours (or very close) during the shortest daylight day of the year, December 21st. So for people moving around on the west coast, here’s a comparative glimpse on the number of daylight hours during these shortest days of the year:
In summer, of course, it’s the opposite. The further north you go, the longer the days, while the closer to the equator, the shorter the days (and the smaller the swing between summer and winter).
During these “shortest days of the year“, a later sunrise and earlier sunset are really noticed. In Spokane (about the same as Seattle) the sun is coming up at 7:33 and setting at 3:59pm vs the San Jose area’s 7:16 sunrise and 4:52 sunset (8:26 hours of sun up north vs 9:36 in the south Bay Area – 1 hour, 10 minutes more sun here).
How does this compare to other major cities around the US? How many hours of sun are they all getting during these darkest days?
New York City 9:13
San Jose 9:36
Los Angeles 9:53
San Diego 10
Seeing the wide differences in sunlight hours alone, I can see why “snowbirds” would migrate south in winter!
Another factor to consider is how much sun you actually see during those hours of daylight! The San Jose area gets only about 20″ of rain during most years. Most of our rain comes between November and March or April, but even so, it’s unusual to get rain day after day for more than 3-5 days. Normally there are sunny and dry days inbetween patches of overcast, drizzle or rain. The weather will be drier in south county or in the east valley and wetter closer to the coastal foothills (Almaden Valley, Los Gatos, Los Altos). The Santa Cruz Mountains usually hold back the summer fog, leaving the inland areas sunnier and drier than the coast.
Sometimes the winter fog is “ground fog”, or fog from the Pacific which snakes its way inland through the Golden Gate and inches down the bay southward. When that happens, you can sometimes go to the top of the Santa Cruz Mountains and enjoy the sunshine while hiking the trails off Skyline Boulevard.
We have 300 sunny days per year in our mild, subtropical climate. Not bad! Even our winters are not so tough. As one of my Finnish clients said to me recently, “Mary, you don’t really have winter in San Jose!”