Weather in San Diego in September
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Compare car hire prices → Affiliate link — we earn a commission at no extra cost to youIn September, San Diego sees average highs of 25.6°C (78.1°F) and lows of 18.3°C. Conditions are warm and mostly dry with only occasional showers, with roughly 10.5 hours of sunshine a day. Weather-wise, this is one of the most reliable months to travel. For the complete picture, see the best time to visit San Diego — every month compared. Once you know when to go, find your San Diego packing list at 247PackingList.
Get ready for San Diego in September
Search flights to San Diego
Compare 100+ airlines for September — one search, best price.
Search Flights →Hot-weather travel clothing
Sun protection, lightweight layers and a reusable water bottle are essential here.
Check Price →What to pack for San Diego in September
- Light layers
- Sunscreen
- T-shirts and light trousers or shorts
Compare all months in San Diego
| Month | High | Rain | Rating |
|---|---|---|---|
| January | 17.3°C | 64.6mm | 10/10 |
| February | 18.1°C | 30.5mm | 10/10 |
| March | 17.2°C | 81.3mm | 10/10 |
| April | 19.2°C | 30.3mm | 10/10 |
| May | 20.3°C | 5.3mm | 10/10 |
| June | 22.1°C | 3.5mm | 10/10 |
| July | 24.1°C | 6.1mm | 10/10 |
| August | 25.5°C | 11.2mm | 10/10 |
| September | 25.6°C | 17.5mm | 10/10 |
| October | 23.9°C | 8.8mm | 10/10 |
| November | 21.1°C | 26.8mm | 10/10 |
| December | 17.9°C | 44.4mm | 10/10 |
Full month-by-month guide: best time to visit San Diego →
For facts about United States — currency, language and dialling code — see our United States country guide at 247CountryInfo. Travellers also find it useful to keep a San Diego travel guide to hand. Check clothing sizes in United States before you shop.
Frequently Asked Questions
Is September a good time to visit San Diego?
September rates 10/10 for visiting San Diego — excellent time to visit. Expect average highs of 25.6°C, 17.5mm of rain across the month and about 10.5 hours of daily sunshine.
What is the temperature in San Diego in September?
In September, San Diego has average highs of 25.6°C (78.1°F) and average lows of 18.3°C (64.9°F).
Does it rain in San Diego in September?
Not much. September averages just 17.5mm of rain in San Diego — the odd shower is possible but most days stay dry.
What should I wear in San Diego in September?
For San Diego in September (25.6°C highs / 18.3°C lows), pack light layers plus sunscreen, t-shirts and light trousers or shorts.
More essentials for San Diego in September
Packing cubes
Keep the bag organised whatever the weather — compression cubes for every size.
Check Price →Travel first aid kit
Compact TSA-friendly kit for peace of mind wherever you travel.
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Climate data sourced from Open-Meteo (open source, open data licence). Monthly averages calculated from 2020–2023 historical data. Weather can be unpredictable — always check a live forecast before travelling.