I'm planning on travelling to San Francisco and Yosemite in October. Just wondering what the weather conditions are normally like so that I can pack appropriately. Thanks!

Anytime you visit San Francisco, it's best to dress in layers. The mornings will be chilly, but it can warm up by the afternoon and then it will usually get chilly again by the evening.

What egret says is true, but it's also true that there's no such thing as "normal" San Francisco weather. San Francisco weather is completely unpredictable. It can be 80 degrees one year on October 10th and 62 degrees the next year on October 10th. Bring a warm jacket and bring a sweatshirt. Probably no need for a raincoat, unless the trip is in late October, in which case you might need that too.

You will be in two different weather zones, coastal S.F. and mountain Yosemite. The later it gets in October the bigger the difference will be.

October can be very warm in the city - what most people call our "indian summer". Typically, there will be about three warm to hot days with cooler nights, then a cool-down of a few cloudy days, then the cycle begins again. This continues until the rainy season begins and breaks the pattern.

October in Yosemite could have warm afternoons but much, much cooler evenings. It would not be unusual to have a snow flurry at higher elevations. I would definitely bring a warm jacket for this portion of the trip.

I cannot overestimate the importance of layerable clothing for your trip. Make sure all your outer clothing can accommodate a t-shirt and then a light sweater underneath.

Definitely bring layers, as others have said.

SF weather is by no means extreme, but it is a bit unpredictable. October is a nice time to visit though as you will likely not have a lot of coastal fog, so the views will be good. It might be warm enough for shorts, but more than likely, long pants and a few layers on top will work well.

Yosemite will be getting cooler and might be downright cold, esspecially in the evenings and early mornings. Snow is rare that time of year though - California doesn't generally get any storms of any magnitude until mid-November. So again, long pants and layer up. In the day time it might be warm enough for shorts.

You shouldn't have any need for a down jacket or anything like that.

Thanks for the tips.