Planning a trip to San Diego in September? You are in luck! The weather is generally good, with an average maximum temperature of +75°F and approximately 6 sunny days. Just be prepared for some rain, as there are usually around 4 rainy days and 10 mm of precipitation. Expect good weather and pack accordingly to enjoy the outdoors. Search flightsin one click on Avionero.
Good to know:
September is usually the hottest month of the year in San Diego;
Average weather
☀️
+75°F
Avg. max. temperature
+55°F
Min.
+100°F
Max.
10 mm
Total precipitation
75%
Avg. humidity
2 m/s
Avg. wind
6 ☀️
Sunny Days
20 ⛅️
Cloudy
4 🌦
Rainy
Our opinion: San Diego has good weather in September.
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Average temperature in San Diego in September
Here are the expected maximum, average and minimum temperatures in San Diego for September based on the historical data.
Last Year
Historical Data
Going from a maximum of +82°F during the day to a minimum of +63°F during the night, the temperature in September averages around +75°F.
The average maximum temperature goes down 27% by the end of the month, compared with the beginning of the month, from +75°F to +70°F.
Is San Diego warm or cold in September?
San Diego is typically warm in September.
Maximum temperatures go up compared to the previous month from +75°F to +75°F. The minimum temperature also goes up from +66°F to +66°F.
It’s generally warm, but pack a long-sleeve shirt for evenings.
September is the hottest month in San Diego, here is the comparison with other months:
Water temperature in San Diego in September
Water in San Diego in September is Fresh. It varies from +64°F to +70°F, with an average of +67°F.This is almost similar to the air temperature, which averages +75°F.
The water temperature in September is one of the warmest of the entire year:
The warmest water temperatures in San Diego are reached in August, when the average sea temperature rises to +68°F. The coldest water temperatures are in February, with an average of +59°F.
Can you swim in San Diego in September?
Water temperature (+67°F) in San Diego in September might be suited for short swims and acclimatized swimmers might find it refreshing.
🦭
Cold
Below +61°F
🏄♂️
Fresh
61°F - 70°F
🏊
Comfortable
70°F - 77°F
👙
Warm
77°F - 82°F
🔥
Very warm
+82°C and up
Think of bringing a full-body or shorty wetsuit (3mm-5mm thickness) to provide insulation and maintain body heat.
Climate in San Diego in September
San Diego weather looks like this, on average, in September and the surrounding months.
August
September
October
Avg. temperature
+75°F
+75°F
+73°F
Min. temperature
+61°F
+55°F
+48°F
Max. temperature
+88°F
+100°F
+97°F
Rainfall
4 mm
10 mm
20 mm
Wind
3 m/s
2 m/s
2 m/s
Avg. water temperature
+68°F
+67°F
+65°F
Humidity
76%
75%
71%
Air pressure
1012 HPa
1011 HPa
1013 HPa
Sunny days
5
6
8
Cloudy days
24
20
17
Rainy days
2
4
6
Snowy days
0
0
0
September weather is still as good as in August.The temperature levels stay the same in the area of +75°F for average maximum temperature during the day.Prepare for more rain. Average rainfall goes from 4 mm to 10 mm.It feels drier, as humidity decreases from 76% to 75%.Winds are calmer in comparison to August, going down from 3 m/s to 2 m/s on average.The good news is there are likely to be more sunny days in September, from 5 to 6.
October brings much the same weather, it remains good.
Wind speed in San Diego in September based on historical data.
Last Year
Historical Data
The average wind speed is 3 m/s getting up to 4 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in San Diego is gradually increasing during September, going from 3 m/s to 3 m/s over the course of the month.
Rain
Amount of rainfall in mm during September in San Diego based on historical data.
Last Year
Historical Data
Typically, there is a 23% chance of rain on an average day in September, with total rainfall of approximately 45 mm. The maximum amount of rainfall per day is around 34 mm, which is moderate rain.On average, there are about 7 rainy days during September, so prepare to bring an umbrella.
Here’s how September is compared with other months in the amount of precipitation, total mm:
San Diego wettest month is February, where a typical day has a 34% chance of precipitation and 84 mm of rainfall per day. July, on the other hand, is the driest month with a mere 6% chance of precipitation and 2 mm of rainfall per day.
How was the weather last September in San Diego?
This is the weather in San Diego in September 2023:
1 September
☁️
+76°F
2 September
🌫️
+77°F
3 September
☁️
+77°F
4 September
☁️
+74°F
5 September
☁️
+73°F
6 September
☁️
+76°F
7 September
☀️
+76°F
8 September
☀️
+79°F
9 September
☁️
+81°F
10 September
☁️
+81°F
11 September
☁️
+82°F
12 September
☁️
+76°F
13 September
☁️
+74°F
14 September
☁️
+74°F
15 September
☁️
+72°F
16 September
☁️
+71°F
17 September
☁️
+70°F
18 September
☁️
+74°F
19 September
☁️
+74°F
20 September
☁️
+73°F
21 September
☁️
+72°F
22 September
☁️
+71°F
23 September
☁️
+74°F
24 September
☁️
+73°F
25 September
☀️
+73°F
26 September
☀️
+76°F
27 September
🌫️
+75°F
28 September
☁️
+72°F
29 September
☁️
+70°F
30 September
☁️
+70°F
In September 2023 San Diego had 4 sunny days, 24 cloudy days, and 0 rainy days. The average maximum temperature was +75°F, with an absolute maximum of +82°F and a minimum of +70°F. The average humidity was 80%, with a maximum of 100% and a minimum of 60%. The average wind speed was 3 m/s, with a maximum of 7 m/s and a minimum of 0 m/s.
Are you planning a trip in September?
Climate Change Over the Years
This is how San Diego climate has changed over the last 43 years.
The climate in San Diego in September has not changed that much over the last 43 years.
The average temperature was the lowest in 2001 (+67°F) and the highest in 2014 (+74°F). The driest year was 2002 with only 156 mm of rainfall, and the wettest year was 2023 with 1311 mm.
FAQ
Frequently asked questions about the weather in San Diego in September:
Is September a good time to visit San Diego?
September is a really good time to go to San Diego. The weather is nice so plan your packing around outdoor activities and exploring. Check out other good time to visit San Diego.
Can you sunbathe in San Diego in September?
September is warm in San Diego. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.
Can you swim in San Diego in September?
In general, you can swim in San Diego in September, if you want to, at an average water temperature of +67°F. But it will feel quite cool, and some precautions are necessary to ensure your comfort and safety.
Is San Diego rainy in September?
San Diego is usually dry in September. Plan your packing around outdoor activities and exploring.
Is it sunny in San Diego in September?
Usually, it’s not very sunny in San Diego in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.
For this page, we’ve looked at the typical weather in San Diego, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
