When you see one here’s how to photograph it

The recent rain storms that we’ve recently experienced not only brought much needed precipitation to drought-stricken California but they’ve also offered a few opportunities to see and photograph their byproducts: rainbows. 

There are two main ingredients for rainbows to appear. The first is rain. Raindrops act as tiny prisms. They refract light causing it to separate into its component wavelengths which we see as the colors of the rainbow.  Next, you need a light source, usually it’s the sun. In the case of rainbows the sun needs to be at a certain angle. It should be at about 40 degrees relative to your position. That’s why you can’t see a rainbow at midday when the sun is about 90 degrees.

Another ingredient is a dark background. It isn’t a necessity for a rainbow to appear but it’ll help make the rainbow appear brighter. Fortunately, as a storm passes and the sun comes out. The clouds can darken the distant sky and make the rainbow pop out more. 

For the most part the sun doesn’t shine during storms and vice versa. That’s why you don’t see rainbows all the time. they usually occur when the rain is almost over when the sun breaks through the clouds. There can be enough rain still lingering in the sky for the sun to create a colorful arc of a rainbow. If the rain completely stops or if the clouds re-form to block out the sun then the rainbow will disappear. Because rainbows often appear at the end of a storm you’ll have work quickly before they fade away.