Rainbow is a census-designated place (CDP) in northern San Diego County, California.

[4] According to the United States Census Bureau, the CDP has a total area of 11.0 square miles (28 km2), all land.

The racial makeup of Rainbow was 1,324 (72.3%) White, 19 (1.0%) African American, 12 (0.7%) Native American, 43 (2.3%) Asian, 12 (0.7%) Pacific Islander, 371 (20.3%) from other races, and 51 (2.8%) from two or more races.

There were 780 housing units at an average density of 48.5 per square mile (18.7/km2).

The area, previously known as "Vallecitos" (little valleys), was renamed "Rainbow Valley" in the late 1880s, after Mr. James Peebles Marshall Rainbow, who bought a homestead there.

[8][9] In October 2007, the Santa Ana winds fueled a major wildfire in the area.

The town has many palm tree farms, and is a gateway to the city of Temecula.

In the California State Legislature, Rainbow is in the 40th Senate District, represented by Republican Brian Jones, and in the 75th Assembly District, represented by Republican Carl DeMaio.