Unlike the day-lubbers, our main concern is not temperatures. We need cloud cover, wind patterns, fog distributon, and the depth of the marine layer. Here's the good sites...
SF/Monterey Bay detailed weather forecast , Local
NOAA , Sky&Telescope
Weather links Page , PurpleAir SmokeMap , NRL Monterey Bay Weather Sat
|Satellite Imagery - stills||NCAR RAP Realtime Weather||Ryan Mauae's Weather.US Detailed Forecasts|
|Balloon soundings||SF Bay Area Current Fog from GOES||Cloud Cover for NorCal||Cloud Cover for Southern CA|
|NCAR realtime Java cloud conditions||Real time Silicon Valley from Mt. Hamilton||Accuweather satellite IR satellite loop|
|Accuweather maps||Live views of other SF Bay locations||West Conus Loop, good detail|
|IR color loop for California||darksky.net||Astrospherics (good!)|
GOES Satellite Loops: Western List, including: San Francisco Area , Hanford/San Jaquin Valley WestCentral (CA,NV) , GOES viewer
Selected ClearSkyClocks in Monterey Bay General Area...
|Cabrillo Observatory and 5-day forecast||Mt. Lassen|
|Bonny Doon Airfield||Mono Hot Springs area|
|Carrizo Plain National Monument and 5 day forecast||Chews Ridge|
|Russian River area||June Lake / Mammoth|
|Lake Del Valle||Oak Ridge Observatory|
|Fremont Peak State Park||Condon Pk/Laguna Mtn|
|Pt Reyes Peninsula||Tomales Bay (Marshall)|
|Grandview Campground (Inyo Mountains)||Mercey Hot Springs|
Astro Weather Panel (a more detailed product similar to ClearSkyClocks)
Balloon soundings. Once you're in, click on the map's "OAK" symbol to get a table of the latest balloon data from Oakland. To determine the depth of the marine layer, look at the temperature and the humidity beginning at sea-level. Look for a sharp drop in humidty and rise in temperature. The elevation of this transition is the top of the marine layer and will correspond to the tops of the fog. This elevation is fairly constant throughout the SF and Monterey Bay area. The highest accessible point in Bonny Doon is at 736m (2400 ft.), and other of our favorite nearby observing sites.
For excursions to the hinterlands, including cross-country skiing and desert foray's..
Snow Cover in California
Yosemite Webcams and, Yosemite Road Conditions
Hwy 120 Road Conditions
Badger Pass Snow and weather
Mono Lake/Conway Summit Webcams
Webcams in the Sierra Ski Zones
Yosemite CDEC stations map , Yosemite Weather
CA Dept Water Resources Stations (including live snow depth)
CA Regional Snow Cover from NOAA
Current Snow Depth Station Data and Sierra Stations Snow Depth from NOAA
China Lake Naval Center's weather site.
My Planning Strategy
If there's an event or photo trip planned, I'll start with the satellite weather , especially the Central California page, to see if there's any storm-related weather coming in soon. If that's OK, I'll see what the fog pattern is on the satellite map. Does Bonny Doon, etc. poke above the fog tops, etc. If there's no fog, but there's a marine layer of damp cool air which may saturate when evening comes, I'll go to the balloon sounding site and find the elevation of the top of the marine layer. Then, I'll go to my list of local observing sites and find one which is above the marine layer and reasonably close.