In the continental United States the prevailing direction of the wind is from west to east. Cities on the west coast/windward side of the continent will have their temperatures moderated by the wind coming off the Pacific Ocean and will have cooler summers and milder winters. Cities on the east coast/leeward side are not influenced as strongly by the Atlantic Ocean as the prevailing wind is blowing offshore.
Below is a map showing lines that connect equal temperatures in the United Sates. These lines of equal temperature are known as isotherms.
Cloud cover also acts as a temperature control. On a cloudy night the clouds act like a blanket absorbing outgoing radiation from the surface of the Earth. The clouds help keep the air temperature higher than on a clear night.