I was just wondering what the temperatures and weather is like in California in early to mid December? My friend and I will hopefully be driving from San Francisco to San Diego in December and are just wondering how warm it will be?!
Here are the averages for San Francisco. You can easily do a similar search for San Diego and other places along the way.
My experience is limited to San Francisco, but San Diego does look similar. I’d expect it to be cool but not cold. You’ll probably run into some rain or overcast weather but it shouldn’t be miserable all the time.
Bring a light jacket and pants; expect 50s and 60s in the day. And drive the Pacific Coast Hwy. 
San Diego can vary, but not a wide variance.
You may get rain, you may not. Rainy days have a high of about 60 degrees. “Cold” rainy days can have a high of 55.
You may get warm Santa Ana wind conditions, you may not. If this happens, it could be sunny and 80 degrees.
On average, though, it’s overcast, sometimes it burns off by midday and you get some sun. Expect the high temp to be about 65. Pants and a light jacket is usually just fine.
But the Central Valley is so lovely that time of year! 
Only if the fog of cow farts is your thing. 
That’s just mean. 
Gosh it is going to be so hard to decide what to do! We want to go to the Grand Canyon too!
How much time do you have?
I live in the Central Valley, he’s being nice.
Definitely take Highway 1
And if you should end up in NorCal (the REAL North, not measly San Fran), shoot a message and I’ll show ya around!
I was kidding. I’m sure there are lovely parts of the Central Valley. However, my experience is limited almost entirely to driving up and down the 5 between SF and LA, which is about as much fun as driving through west Texas.
Cool!! I’ll let you know 
How much time?!
Hmmmm well! I’m not entirely sure, we want to be home before Christmas Eve and will be coming from New Zealand. Originally it was just going to be a week in San Francisco alone, then it stretched to two weeks, and then we read all of the guide book…
BAD IDEA!
Now we want to go everywhere and so we aren’t so sure. I definitely want to hire a car and drive down south, but the Grand Canyon does look sooo amazing?!!
We need to pin point exactly where we want to go more specifically!
Yeah, the Grand Canyon is way the fuck out of the way. Wait until you are out to Las Vegas and then go and see it then. Tahoe and Yosemite are much more accessible from San Francisco. Stop in Santa Barbara and I’ll buy you a beer!
Have you ever driven in the U.S. before? Things are much farther apart than you may be used to. For example, the distance from Los Angeles to San Francisco is about the same as the distance from London to Glasgow.
Ooooh I have that problem. I recently bought a guidebook to California (I was looking for museums), and now everything looks good. Fortunately I live here, so I have a home base to go from, haha.
It’s a huuuge state. Perhaps narrowing down your area of attack could help. I mean, San Fran to San Diego and the Grand Canyon? Google Maps says that’s about a thousand miles.
Edit: Seconding Yosemite. If you’re looking for amazing natural scenery, Yosemite’s your place.
The American West is huge. Stopping off at the Grand Canyon on the way from San Fransisco to San Diego is like stopping off at Rome on the way from London to Lisbon.
I’d actually recommend doing that in the opposite direction (south to north)… as that way, you’re not on the outer edge of the road with the steep dropoff in places.
I do however concur that it’s a lovely drive and well worth it - especially when you get well north of Los Angeles.
So true… though I’d almost say it’s like stopping off on the way from London to Paris - really completely out of the way.
Sample trip map:
direct from SF to SD (via interstate - fast but boring)
Taking a “side trip” to the Grand Canyon - again mostly interstate.
I actually think hitting the Grand Canyon is a dandy idea - it’s STUNNING - but you might want to rethink your flights into/out of the US. Fly into SF, drive down to SD, then go to the Grand Canyon - and fly out of either Phoenix (closer to the South Rim) or Las Vegas. Sample route from SF to SD then to GC. The Grand Canyon is really only worth a day unless you’ll be hiking. The weather there during the daytime in December (from our visit 3 years ago) went from a high of 50s (Fahrenheit) one day to a high around 32 (F) the next day and it was pretty windy. There are a number of other places to see within a day’s drive of the Canyon, however.
I’ve lived in So Cal, mostly SD from 6th grade on. Also, until a few years ago I used to make the trip you’re describing about 4 times a year so let me tell you what to expect.
If you take Hwy 1, (by the coast) it will be beautiful, overcast and cold in December. Probably raining for the first half of the trip. Not the best time of year to drive it. Speed limit If I remember is about 45. You’ll go much slower due to slower traffic. It will be a very long day driving.
If you take Hwy 5, you’ll leave SF and head east for about 30 minutes then turn south when you hit Hwy 5. It will be about 225 miles of road that is as straight as they come. There is a little sigh of civilization, typically a gas station or Jack in the Box about every 35 miles. About 100 miles into it you make a 3 or 4 degree turn to the east and then it’s another 100 miles of straight road. People drive 80+ on that 2 lane road and fight with the trucks for the left hand lane.
If you continue further east from SF to Hwy 99 you’ll have civilization most of the way. More scenery to look at. 3 lanes most of the way. Far fewer trucks and slower speeds - 70 - 75mph.
Both meet around Bakersfield. From Bakersfield to the top of the Grapevine is another 20 - 30 minutes. Pretty soon you’ll pass Magic Mountain and that means you’re 150 miles from SD. Another 40 - 45 miles to LA. (Burbank = 130 miles more, Firestone plant = 111 miles more, Disneyland 85 miles more, Border checkpoint 49 miles more - like I said, I’ve driven it tons of times.)
Plan your trip so you don’t hit LA after 4pm or before 7:30pm or it will take you 2 hours to make that 35 miles through LA. Thereafter, traffic continues although it is moving ringht along all the way to SD.
Total Trip -
Hwy 1 - all day long
Hwy 5 - about 6 1/2 - 7 hours. (assuming you time LA correctly)
Hwy 99 - about 7 - 8 hours. (assuming you time LA correctly)
Weather in SD in December is cool @ 65 +/- degrees. Rain sometimes but not all that often or for more than a day. Typically partially cloudy. Water temp about 60 - 62 degrees. Wind light and off the ocean. It’s great but don’t tell anyone.