Planning a CA coast (San Fran to San Diego) trip for Jun 13th-23rd. I've heard that fog/smog rolls in... Where and When? Will we be looking at fog for our drive south on Route 1?

At that time of year and during most of the summer, fog is prevelent along the entire coast and sometimes for the entire day. It depends on how hot it gets in the Central Valley. There's no way to predict it far in advance.

At Pebble Beach, the pros played golf this past February in short sleeved shirts under clear and balmy skies. While at the US Open a few years ago there in June, they had to wear sweaters and hardly saw the sun.

That said, a lot of people in California head to the coast in the summer to escape the heat. So, you will not be alone.

Oct is a big month for fog. There isn't too much smog along the coast. If you are taking HWY 1 (PCH) from San Fran to San diego, You should be fine. If there is fog, it most often lightens up around 11:00ish.

Also you can take HWY 1 (PCH) almost all the way to San Diego. Once you hit, Dana Point, you'll have to hop on the 5 FWY to get to San Diego. Once you get to San Diego, stop along the way in La Jolla, it's beautiful, and great beaches. Have fun. If you're looking for some great places to stay, my vote is La Jolla. It's just too pretty to pass up for a visit.
http://sandiego.nyctourist.com/

Having grown up in La Jolla I can tell you that, yes, it is beautiful, but the fog and coldish weather - called June Gloom by the locals - is at its height in early June. I wouldn't count too heavily on beach days! That said, if you are ending your trip in San Diego, you are less likely to hit this weather. It is generally gone by the end of the month.

I think Travelattorney might have made a typo. October is our best month for fog-free weather along the coast. June is really "iffy".

Also, there is no such thing as PCH in Northern California - it stops somewhere around Santa Barbara or San Luis Obispo & becomes the Cabrillo Highway.

Stu Dudley

"Oct is a big month for fog" Huh?? StuDudley is correct -- mid Sept through Oct is the LEAST foggy time along the coast.

liveforadventure: As the others say - there is no way to tell for sure more than a day or two ahead, but it is more likely than not that you will have some fog. Pray for mild temps inland while you are here - Fog on the coast get much worse the hotter it is inland. When It is 100+F in the Central Valley, it can be low 60's and foggy just across the hills in San Francisco.

One thing we were ill-prepared for in a July in SF is how cold it gets in the evening in the fog. We spent a July 4th watching fireworks wearing every item of clothing we had with us - it was freezing. Being from the east coast, we expected summer in California to be hot - but that was in my pre-Fodors days or else I would have been better informed.

The coast of California has the dreaded fog typically early morning, late afternoon and sometimes in betweeen.Inland you'll mostly find it warm to hot. Its the micro-climate that makes Calif. weather so different. You can be on the coast close to the ocean, freezing cold in July but drive a short 15 min. inland and there you have it, all the warmth your little heart desires

PCH takes a "jog" inland at Morro Bay to San Luis Obispo which is 101--south until Gaviota where it once again is "coastal"
"lvitaly" really hit it about going inland for warmth..
Morro Bay can be foggy & 60 -11 miles to SLO --84
Totally unrelated note about SLO--If yoiu are there on a Thursday Be sure to take in their Farmers Market--which is produce Plus, lots of great food and often local entertainment

Living in the SF Bay area for over 16 years, I can say that June can be clear or foggy but most likely foggy in the morning and may burn off by afternoon. Our best coastal months are towards the fall when the fog is gone and the temps are higher.

In reference to smog...not much of it in the SF area but I know that down south it can get "stuffy".

I don't recall ever seeing marine layer roll in, although, it‘s fog I tend to think of fog as the stuff you can see rolling in. Not sure I've ever noticed what month the fog starts to roll in but late fall, winter sounds about right.

In June, it’s a marine layer that is just constant in the mornings here in San Diego. Usually, burns off by noon. Smog doesn't roll in from the coast, as it's created inland and either stays there or moves out to east county.

Sounds like a fun trip, I hope by the time you get to San Diego, we have sunny mornings for you to enjoy.