Climate and monthly weather forecastSan Diego, CA

The climate of San Diego

Situated in southern California, San Diego boasts the highly predictable BSk classification of climate, known as mid-latitude steppe climate according to the Köppen climate classification system. Throughout the year, San Diego enjoys a mild climate with variations in temperature, humidity levels, rainfall, and other weather parameters lending a unique characteristic to each changing season.

Specifically, high temperatures throughout the year range from 63.1°F (17.3°C) to 77.4°F (25.2°C) with the warmest month being August. The lowest temperatures, varying from 51.8°F (11°C) to 65.7°F (18.7°C), occur in December and August. The relative humidity throughout the year fluctuates from 59% to 73%, contributing to the overall comfort or discomfort level experienced by inhabitants and visitors alike in San Diego.

Rainfall in San Diego exhibits a pattern of fluctuation throughout the year, adding up to 0.12" (3mm) in the driest month of June and reaching up to 1.65" (42mm) in the month with the heaviest precipitation, December. The number of rainfall days in a month varies equally, hitting a low of 2.7 days in June while peaking at 7.6 days in March.

In San Diego, daylight hours range from 10 hours in December to 14.3 hours in June, the longest daylight month. Correspondingly, the amount of sunshine in hours varies from 6.7 hours in December to 11.9 hours in July, with June, July, and August all boasting ample sunshine hours.

The best time to visit San Diego

The ideal time to visit San Diego depends largely on individual preferences, particularly when it comes to the desired weather and temperature. For those who prefer a cooler climate; however, the best time for a visit would arguably be in the months from November to March. During these months, temperatures average between 63.3°F (17.4°C) and 68.5°F (20.3°C), while relative humidity levels remain steady, averaging between 59% and 64%.

For those desiring a warmer climate aligned with long daylight hours, the months of June, July, and August are the best. During these months, San Diego experiences temperatures as high as 70.7°F (21.5°C) to 77.4°F (25.2°C) and enjoys the longest daylight hours of 14.1 hours to 14.3 hours.

The worst time to visit San Diego

Just as the best times to visit San Diego are subjective and hinged upon personal preference, the same is true for identifying the worst time to visit the city. Nevertheless, for those not keen on higher levels of humidity, the months between May and September might be best avoided as humidity levels reach their peak during this period, going as high as 72%-73%.

Spring weather in San Diego

Spring, spanning March, April, and May, welcomes tourists with mild weather. Temperatures fluctuate between 52.7°F (11.5°C) to 67.6°F (19.8°C), while rainfall levels drop significantly from 0.83" (21mm) in March to 0.39" (10mm) in May. This period also signals an increase in daylight hours, with an average range from 12 hours to 13.9 hours.

Summer weather in San Diego

San Diego's summer season, encompassing June, July, and August, is characterized by warm temperatures ranging from 58.8°F (14.9°C) to 77.4°F (25.2°C), and minimal rainfall, with the lowest rate of 0.12" (3mm) in June. Tourists who love longer daylight hours will relish summers in San Diego where daylight can last from 14.1 hours to 14.3 hours in a single day.

Autumn weather in San Diego

In the autumn months of September, October, and November, temperatures begin to drop from 65.1°F (18.4°C) to 63.3°F (17.4°C) and rainfall begins to increase, reaching 0.87" (22mm) in November. Material changes in daylight hours start to become noticeable, moving from 12.4 hours in September to 10.5 hours in November.

Winter weather in San Diego

Winter in San Diego, stretching across December, January, and February, is mild with average high temperatures ranging from 63.1°F (17.3°C) to 64.4°F (18°C) and average low temperatures hovering between 51.8°F (11°C) and 52.7°F (11.5°C). December features the highest levels of rainfall at 1.65" (42mm), and sees daylight hours at their shortest, averaging at 10 hours. This period is marked by relatively low humidity levels, averaging between 59%-64%.

Weather in January

January in San Diego rings in the New Year with slightly cooler temperatures and increased precipitation. This month sees a slight dip in average high temperature from 64.2°F (17.9°C) to 63.1°F (17.3°C). With an average rainfall of 1.06" (27mm), it is not the wettest month, but it is close. Weather in January »

Weather in February

February brings subtle changes to San Diego's weather pattern. This month experiences a slight ascend in relative humidity to 64%, with an expectation of more occasional rain showers. The slight increase in rainfall to 1.5" (38mm) might be an indication of a wetter period. Weather in February »

Weather in March

In March, the weather in this Californian city starts to lean towards spring. With a small decrease in rainfall to 0.83" (21mm), there is a noticeable shift in the climate. While it does get a little windier, with average wind speeds increasing to 6mph (9.7km/h), clear and sunny days dominate the scenery. Weather in March »

Weather in April

April welcomes much-welcomed improvements to San Diego's conditions. The precipitation drops even further down to 0.67" (17mm), as rainfall becomes less frequent. The month also sees a significant increase in sunshine hours, elevating to 10.9 hours, and adding warmth and brightness to the scenario. Weather in April »

Weather in May

San Diego embarks upon its summer season in May. There is a noticeable decline in rainfall, dropping to 0.39" (10mm), indicating the beginning of a drier season. With the increase in temperature, there is a considerable augmentation in humidity to 72%, adding a hint of heaviness to the air. Weather in May »

Weather in June

June in San Diego sees a further rise in temperature and abundance of sunshine. With a dip in rainfall to a minimal 0.12" (3mm), it is one of the driest months. Prolonged sunlight and low cloud coverage allow for more outdoor activities, with beachgoers relishing in the highest sea temperatures. Weather in June »

Weather in July

July is a standout month for San Diego, boasting the hottest temperatures of the year, peaking at an average high of 75.4°F (24.1°C). It is the epitome of summer weather with hot days and warm, comfortable nights. This month embraces quality beach weather, and it offers some of the year's best conditions for water sports. Weather in July »

Weather in August

In August, the summery ambiance continues in San Diego. With the highest average high temperature of 77.4°F (25.2°C), the city revels in peak summer. The month starts with an upswing in sea temperatures while the extended daylight hours encourage outdoor activities. Weather in August »

Weather in September

September in San Diego offers the residents and visitors a bit of everything. The air begins to cool from peak summer temperatures, averaging a high of 76.6°F (24.8°C). With humidity dropping to 68%, the heaviness in the air lightens, and the skies remain clear most of the time. Weather in September »

Weather in October

October in San Diego is characterized by cooling temperatures, shorter daylight hours, and a slight increase in rainfall, measuring at 0.31" (8mm). The sea temperature deals with a significant dip, dissuading people from entering the waters. Weather in October »

Weather in November

November continues to embrace San Diego's cool climate, but with an added touch of moisture. With rainfall levels rising up to 0.87" (22mm), there is an evident shift manifesting towards further precipitation. Autumn foliage colors the city, and residents enjoy the changing scenery. Weather in November »

Weather in December

December ushers in the winter season in San Diego, though winters here are relatively mild compared to most other parts of the United States. There is a noticeable increase in conditioned precipitation, with rainfall levels peeking at 1.65" (42mm). Weather in December »