San Diego Weather in September
“The kind of pleasant weather you build a trip around.”
Roughly 2 rainy days across the month, on average.
September is widely considered one of the finest months to experience San Diego. The summer rush begins to ease, yet the climate stays gloriously warm, with average afternoon highs reaching a pleasant 25.5°C and mild evening lows hovering around 18.4°C.
With roughly 10.7 hours of bright sunshine daily and a negligible 14mm of rainfall spread across just 1.5 days, outdoor plans are virtually guaranteed to remain dry and sun-drenched. It is the golden hour of the Southern California coast, offering tranquil beach conditions and gentle Pacific breezes.
The city runs on microclimates: it can be 18C and foggy in Ocean Beach while it's 32C and dry in El Cajon, 20 miles apart. Locals never say 'San Diego' for their neighborhood — it's Hillcrest, North Park, Barrio Logan, or PB. The Convoy district in Kearny Mesa has better Sichuan and Korean food than anywhere in LA, and no tourist ever finds it. 'Freeway' takes 'the' — 'the 5,' 'the 805.'
What to pack for San Diego in September
- Breathable cotton or linen shirts for warm, sunny afternoons
- Light knit sweater or denim jacket for cooler coastal evenings
- Polarized sunglasses and a wide-brim sun hat
- Comfortable walking sneakers or supportive sandals
- Swimwear and high-SPF sunscreen for beach outings
What to pack for San Diego in September
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Where to stay in San Diego
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Compare hotels on Booking.com→Estimated September trip to San Diego
Shoulder-season pricing — a balance of price and conditions. Rule-based estimates from a couple based in London — actual prices vary.
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Things worth doing
Spend peaceful afternoons swimming, paddleboarding, or sunbathing along the shores of La Jolla and Coronado. Take advantage of the clear, dry days by wandering through the shaded trails and museums of Balboa Park, or enjoy an open-air harbor cruise at sunset.
September vs. the rest of the year
How this month compares in San Diego. Tap any month to read more.
highlighted months are among the best time to visit.
Best time to visit San Diego
While September has its own character in San Diego, the data-backed best months to visit San Diego are April, June, July, August. These months combine the most favourable temperatures, rainfall, and sunshine across an 11-year climate record (2015–2025).
See the full best-time-to-visit guide for San DiegoOther places with a similar climate right now
San Diego in September — FAQ
Q01Should I visit San Diego in September?
Should I visit San Diego in September?
Yes — this is one of the best months of the year to visit. In September, San Diego averages a high of 26°C (78°F) and a low of 18°C (65°F), with 14mm of rainfall across roughly 2 rainy days. September-October see the marine layer finally burn off by 10am and water temperatures peak at 21C, prime for La Jolla Cove snorkeling with leopard sharks.
Q02What temperatures should I expect in San Diego during September?
What temperatures should I expect in San Diego during September?
The average high temperature in San Diego during September is 26°C (78°F), with an average low of 18°C (65°F). These figures are averaged from 11 complete years of daily records (2015–2025, Open-Meteo Archive).
Q03Is September a rainy month in San Diego?
Is September a rainy month in San Diego?
San Diego averages approximately 2 rainy days in September, with a total monthly rainfall of about 14mm. This is based on daily precipitation records where days with 1mm or more of rain are counted as rainy days.
Q04How should I dress for San Diego in September?
How should I dress for San Diego in September?
For San Diego in September, pack layered clothing for changing temperatures, sunscreen and sunglasses, comfortable walking shoes. These recommendations are based on 11 complete years of weather averages for this specific month. Light hoodie for June Gloom evenings — the marine layer drops temperatures 10 degrees after sunset even in summer.
Q05Is September a busy travel month for San Diego?
Is September a busy travel month for San Diego?
Tourist crowds in San Diego during September are typically moderate — shoulder season, a sweet spot between crowds and weather. Consider this when planning accommodation — prices track crowd levels closely. The city runs on microclimates: it can be 18C and foggy in Ocean Beach while it's 32C and dry in El Cajon, 20 miles apart. Locals never say 'San Diego' for their neighborhood — it's Hillcrest, North Park, Barrio Logan, or PB. The Convoy district in Kearny Mesa has better Sichuan and Korean food than anywhere in LA, and no tourist ever finds it. 'Freeway' takes 'the' — 'the 5,' 'the 805.'