Termo (also, Snowstorm and Armstrong) is an unincorporated community in Lassen County, California. It is located on the Southern Pacific Railroad 32 miles (51 km) north-northeast of Susanville, at an elevation of 5305 feet (1617 m). This town straddles U.S. Highway 395 north of Ravendale.
In 1900, Termo was the terminus of the Nevada–California–Oregon Railway. The Termo post office opened in 1908, closed in 1914, and re-opened in 1915.
Termo soils are on lake terraces and in lake basins and have slopes of 0 to 2 percent. The mean annual precipitation is 9 inches (230 mm) and the mean annual temperature is 45 °F (7 °C). The ZIP code is 96132 and the area code 530.