These most colorful of sunsets occur when the sun meets the edge of a storm near the horizon. I watch out the window of my house for the right storm conditions. I also check the western satellite views provided by the US weather service on the Internet. I can keep a satellite eye on the storms progress as waves on rain come in off the Pacific Ocean. I am out the door if it looks like it might happen.
Storm chasers get the best shots or nothing at all.
Local television stations have web sites that provide live views of San Francisco and the Golden Gate Bridge. Most of the storms are heading west off the Pacific Ocean. Devil Mountain is 20 miles due east of San Francisco. When the sun comes out in San Francisco it usually means I have 20 minutes to head out in the rain, get in location and wait for the sun and rainbows to appear. I dashed out to Devil Mountain after the seeing sunny live pictures over San Francisco and checking the satellite view on the Internet.