San Francisco's climate is mild with wet winters and dry summers. The coldest month is January (average overnight is 46°F) and the warmest month is September (average day time temperature rises to 71°F). Also January is the wettest month, and July is the driest. Most time of the year, the temperature will be in the 60's and 70's degrees Fahrenheit. Also, because of the city's topography, San Francisco does have a series of so called microclimates. Closer to the ocean on the Western side of the city, in example, there is more fog. Because of several hills in San Francisco, the amount of rainfall is different in different parts of the city.