San Diego (CA) Temperatures: Monthly Averages and Year-Round Insights
On this page, we’ll explore San Diego’s temperature statistics in detail, including day and night variations and monthly averages. We’ll also compare the annual temperature to other cities in the United States of America.
Monthly Temperature Averages
San Diego sees moderate fluctuations in temperatures, making each season distinct yet not extreme. Average maximum daytime temperatures reach a warm 26°C in September. In January, the coolest month of the year, temperatures drop to a pleasant 19°C. At night, expect even cooler temperatures, with lows averaging around 9°C.
The chart below illustrates the average maximum day and minimum night temperatures in San Diego by month:
The minimum temperature is often recorded between 4 AM and 6 AM, while the highest temperature is usually reached at 3 PM. During this time the sun's heating effect is the strongest. September, the city’s warmest month receives 253 hours of sunshine.
The chart below shows the average temperature throughout the year:
January, the city’s coldest month, receives about 35 mm of rainfall spread over roughly 5 days. For more information, please visit our San Diego Precipitation page.
Annual Temperatures in the United States of America Compared
The map below shows the annual temperature across the United States of America. You can also select the different months in case you are interested in a specific month.
very warm
warm
pleasant
moderate
cold
very cold
San Diego Temperatures Compared World Wide
San Diego’s average annual maximum temperature is 22°C. Let’s compare this with some popular tourist destinations:
The city of Rome, Italy, has an average annual temperature of 20°C, known for its sunny summers and comfortable winters.
Meanwhile, Queenstown, New Zealand, the average annual temperature is significantly lower at 10°C, with mild summers and cold winters.
Beijing, China, experiences more extreme temperature shifts, but still averaging 20°C annually.
In Tokyo, Japan, the average annual temperature is 21°C, expect warmer summers and milder winters.
How does the temperature feel?
Humidity is an essential factor in how you experience temperature. When a warm period is accompanied by high humidity, it results in a higher perceived temperature. This is especially true when temperatures exceed 25°C, as it can cause greater discomfort.
In San Diego, during the coolest month, January, you will experience 64% humidity, which is considered high. This is accompanied by an average maximum temperature of 20°C. In the warmest month, September, the humidity is 74% combined with an average maximum temperature of 26°C, which creates a high-feel temperature. Explore our detailed page on humidity levels for further details.
How are these Temperatures Measured?
Generally, temperature data depicting climate is usually given over a 30-year average in order to reduce short-term fluctuations and reveal better long-term trends in climate conditions.
This temperature data is taken from land-based thermometers, ocean buoys, ships, and satellites. These measurements are transmitted to weather stations and climate centers around the globe where they are processed, averaged, and analyzed in order to monitor the trends and create climate models.
Effects of Temperature on Weather and Climate
Temperature variations influence precipitation patterns in Amsterdam:
Rainfall: Warm air holds more moisture, leading to heavier rain during warmer months. However, precipitation is generally moderate year-round.
Snow: Occasional snowfall occurs in winter, though it rarely lasts very long.
For more detailed information about San Diego’s weather, including monthly rainfall, sunshine hours, and humidity levels, visit our San Diego climate page.
Current temperature in San Diego (CA)
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