Depending on the day and time of day and location the temps on your trip will range from low 50s to high 70s. Native Californians have learned to always bring multiple layers in there cars : T shirt, long sleeve shirt, sweatshirt or fleece, and light jacket. You will find yourself putting on and taking off these layers frequently. You will not need shorts.

Too bad you're not here today - it's about 70 degrees in San Francisco, and beautiful, no jacket needed, and people are eating lunch outside.

Next week, who knows, but montereybob gives very good advice.

Another vote for bringing a variety of clothes. Yosemite's weather can change from day to day. It might be mild. It could also snow. Possibly both during a period of a few days.

Definitely layers as montereybob described.

Another recommendation for layers..........

Bring a pair of shorts. They don't take up much room and you might enjoy wearing them more than you think.

Almost 80 degrees here in LA/Sd today and warmer over in Palm Springs. The PGA golfers at Riveria CC are loving it.

"the temps on your trip will range from low 50s to high 70s"

Montereybob and the others seems to have missed that you are also going to Yosemite . . . and snow is forecast for next week.

Today in the central Valley it was 71F and I had the top down all day - next week is supposed to have colder/wet weather.

So - shorts to cashmere, light tops to down jacket/vest (in other words -layers)

Bring a light rain jacket, fleece, and parka (for Yosemite). I find myself wearing all three during this time of year around here. It's gorgeous out today, but last week was cold enough to wear fleece and parka. Better to be prepared than sorry.

Um,no, didn't miss Yosemite. Specifically mentioned it.

Yosemite is forcast to have lows in the 30s, highs in the 50s. Jeans, longsleeved tee, fleece, and a light jacket have always worked for me in those temps as long as I am not planning to be out for an extended period of time in the early morning or overnight.

Shorts in the Bay Area this weekend. We are headed up to ski in the Sierras next weekend so bring hats, gloves,etc. Since you are from such a warm climate, you will find Yosemite very cold. Don't plan to swim in the ocean in Northern California, it is frigid! February is a beautiful time of year to visit.

If you like museums, the Asian Art museum in SF is just beginning to host the terra cotta warriors from Xian, China. You will need tickets.

And the DeYoung has the Dutch Paintings from the Mauritius exhibit through June 2nd.

I don't recall where you're staying, but if it happens to be Fisherman's Wharf area, we had a really good breakfast there yesterday at a place called the Hollywood Cafe. A little pricey, but the portions were huge - we could easily have shared. Even the coffee was noticeably very good.

http://www.hollywoodcafesf.com/

Great input!! Thank you so much. Will eat in Hollywood Cafe. It looks really nice and it's nice going somewhere you have a word of, it makes me feel more confident.
About clothing I synthesize bring a little of everything and be prepare for anything.
I got a question about layering and skiing. What kind of pants do I need to wear during that activity and in general? I read cotton is a BAD idea in cold weather but the best I can do with my "tropical" wardrobe is 50% cotton and 50% polyster jeans or slacks made of rayon and wear 100% nylon or wool tights underneath. Would that be enough?

BTW - welcome to a Tico/Tica. We loved visiting Costa Rica - when my sister lived there.

When skiing - for years we wore the traditional "long underwear" made of cotton - and later the manufacturers added other materials - but just something under another layer of clothing is the point. Newer materials claim they wick away any perspiration, etc - but never found that to be a real problem.

The outer layer should be wind/moisture resistant - to shed the snow/rain you might encounter when skiing - but for your purposes (walking around Yosemite, by the beach if there is a marine layer/fog/wind, etc) - unless there is a driving rain/snow - a pair of ordinary outer slacks should do.

And if Lower Yosemite falls is really flowing - the mist from it forms a big cloud of wet vapor - so you definitely need something water proof/resistant when viewing that. Maybe even a small/portable umbrella.

Just a couple of comments.

The climate in LA and SF is categorized as "Mediterranean Subtropical", like the cities bordering the Mediterranean. We have basically only two seasons, winter, when the rain (hopefully) falls, and summer, when it's dry and sunny. February and March,when you will be here, is winter, and we are hoping for rain because we are below normal so far. Sorry if that happens, but we really need it. Bring an umbrella. Maybe that will bring some rain.

For weather forecasts I like Accuweather.com, But Weather.com will give you similar information. The forecast for LA for the next few days is here.

http://www.accuweather.com/es/us/los-angeles-ca/90012/daily-weather-forecast/347625

And of course you can get it for Yosemite Valley and San Francisco, by just entering their names in the search box at the top.

I hope your trip is enjoyable.

paolala, if you're going skiing you're really going to want ski pants. If you have a pair of leggings those could stand in for long underwear under the ski pants but I really don't think you should try to wear jeans or anything like that. You'll also need a proper ski jacket. I know they rent stuff like that at places in the cities like Mel Cotton's where they rent skis but I'm not sure if you can rent ski clothes at a ski resort. Also you can pick up a ski bib cheap at places like Walmart near where it snows (there's one in Sonora which would be on your way to Yosemite if you took 120) but I don't think jackets can be had for as little.

For the record, the weather has turned back to winter in San Francisco. Yesterday, it was in the low to mid-50s and "brisk", today it's cloudy, a little rainy, and right now, it's in the mid-40s (10 a.m.). The forecast for the rest of the week is mid- to high-50s and partly sunny.

Lots of rain forecasted for this week in SF and it'll be cloudy in LA with a little bit of rain.

I'd suggest bring as warm (layered) clothing as possible. Shorts may not be needed as the highest temperatures even for LA will be in the low 60s.

Have a great trip and welcome to California!

And this is a main reason why I have never gone skiing - all the gear you have to either buy or rent I go play in the snow, do a little snowshoeing, tubing, etc. where regular clothes are sufficient.

November_moon, I think most people that try skiing do it with someone who also skis and then they borrow their stuff. I know we have enough to outfit a few families at our cabin!