Why Is San Francisco California On the West Coast Warmer In Winter Than Washington D.C. On East Cost?

Latitude is only one factor of several that determine climate in any particular region.

San Francisco’s position between 30° and 40° latitude and its location on the western side of the North American continent place it in the climate subcategory called Mediterranean. People living there experience warm, dry summers and mild, wet winters.

Washington, D.C.’s, climate, on the other hand, is classified as humid subtropical, a type of climate that is usually found on the eastern sides of continents. Features of this type of climate include hot, humid summers and periods of severe winter cold.

Other factors that influence climate include elevation, topography, and distance from a large body of water.

Places at high elevations have cooler temperatures than places at low elevations. High mountains affect climate because they form a barrier that blocks moist air on the windward side from reaching the other side, called the lee side.

Winds in the United States generally blow from west to east. For example, Denver, Colorado, has a cool, dry climate because it is on the lee, or eastern, side of the Rocky Mountains.

Places that are close to oceans or large lakes tend to get more rain or snow because the water that evaporates from them fills the surrounding air with moisture.

For example, coastal areas in Oregon and Washington receive high precipitation because winds filled with moisture that has evaporated from the Pacific Ocean move in from the west and then are blocked by the nearby Cascade Mountains.