Weather in San Francisco

Planning your day in San Francisco? In this section, you will find up-to-date information on weather conditions, as well as forecasts for the near future, to ensure your trip is as comfortable as possible.

The climate in San Francisco can be characterized as temperate Mediterranean, with mild temperatures throughout the year. The city experiences neither extremes of heat nor cold, making it comfortable to visit in practically any season.

Two main seasons clearly stand out in San Francisco. Winter, lasting roughly from November to March, is mild here, with average temperatures around 10-12°C, and this is the main period for rainfall, although even that is not excessive. Summer, from June to September, is conversely very dry and sunny, with comfortable average temperatures in the region of 18-19°C. This summer period is practically devoid of rain, creating ideal conditions for exploring the city and its surroundings. Spring and autumn are pleasant transitional seasons with moderate rainfall and comfortable temperatures.

The temperature regime in San Francisco is notable for its mildness throughout the year, without sharp fluctuations. The coolest months are usually December and January, when the average temperature hovers around 10.7-10.9°C. At this time, daytime highs reach approximately 14.3°C, while nighttime lows drop to 7.2-7.5°C. The warmest months are considered to be August and September, with an average temperature of about 19.0-19.1°C. In September, the daytime temperature can rise on average to 24.4°C, while the night drops to 13.9°C.

The summer months in San Francisco, from June to September, are characterized by pleasantly warm weather rather than exhausting heat. Average daytime temperatures fluctuate from 23.0°C in June to 24.4°C in September. Nights remain quite cool, with temperatures around 12.6°C in June and up to 14.0°C in August. Such a difference between day and night temperatures, amounting to about 10-11°C, creates comfortable conditions for evening walks after a warm day. It is worth noting that summer is the driest period, with practically no precipitation.

Winter in San Francisco, from December to February, passes mildly and without frost. Average daytime temperatures during this period are approximately 14.3-15.5°C, which is quite comfortable for walking. At night, the temperature drops to 6.7-7.5°C, so warm clothes will still come in handy. Daily temperature fluctuations in winter are less pronounced than in summer and amount to about 7-9°C. Winter months are also the primary ones for rainfall, although it is not excessive.

San Francisco observes a distinct seasonality in the distribution of precipitation throughout the year. The city has a distinct dry season and a wetter winter period. Given the mild temperatures, precipitation here falls predominantly as rain; snow is an extremely rare phenomenon for San Francisco.

The summer months, specifically June, July, August and September, are absolutely dry. During this period, according to statistical averages, rainfall amounts to 0 mm, and rainy days are not observed at all. This makes summer in San Francisco predictably sunny and ideal for active time spent outdoors.

The main part of annual precipitation falls in the period from November to March. The wettest month in terms of fallen moisture is considered to be December, when an average of 4 mm of precipitation falls. In terms of the number of rainy days, March stands out (about 12 days), followed by January (approximately 11 days) and December (about 10 days). Even in these "wettest" months, the total amount of precipitation remains small, which usually means light or moderate rains rather than prolonged downpours. Transitional months, such as April, May and October, are characterized by minimal precipitation (1 mm) and a small number of rainy days (from 2 to 4).

When packing your suitcase for a trip to San Francisco, remember its changeable weather and famous microclimates. The key to comfort is layering. Even on a warm sunny day, the morning or evening can be cool, especially due to fog or a fresh breeze from the ocean. Therefore, a light jacket, sweater, or fleece that can be easily taken off or put on will become your best friends. And, of course, do not forget comfortable shoes for walking – the city's hilly terrain encourages long walks, and the weather can change from neighbourhood to neighbourhood.

From November to March, when rains are more likely in San Francisco (on average 6-12 rainy days per month with precipitation of 2-4 mm), it is worth taking a light waterproof jacket or an umbrella, as well as warmer clothes such as sweaters and closed shoes, as the average temperature hovers around 10-13°C. For the summer months (June-September), characterized by dry and sunny weather with average temperatures of 18-19°C, t-shirts, shorts or light trousers are suitable. However, do not forget about the cool mornings and evenings (temperatures can drop to 13-14°C) and the famous San Francisco wind – a light jacket or jumper will be necessary. At any time of the year, sunscreen and sunglasses will be useful, as the sun can be active even on cool days.