Early autumn · Weather & things to do
Downtown San Diego & Gaslamp Quarter in September
Downtown San Diego & Gaslamp Quarter edges cooler than August, with highs of 88°F (31°C), lows of 66°F (19°C) and about 0.2 in (6 mm) of rain.
It scores 75/100 for comfort, 10th of 12, which makes it a solid shoulder-season month.
- Avg high
- 88°F (31°C)
- Avg low
- 66°F (19°C)
- Rain
- 0.2 in (6 mm)
- Humidity
- 57%
- Cloud cover
- 59%
- Daylight
- ~12 h 11 min
- Comfort score
- 75/100 · Great
What September feels like
Afternoons run hot at about 88°F (31°C), which leaves mornings and evenings as the time for walking.
Nights cool to an average low of 66°F (19°C).
It's one of the drier stretches, with only about 0.2 in (6 mm) of rain.
Plan around September
September is shoulder season: good weather, a step below the best months (October – March).
- Comfort improves from 67/100 in August to 75/100.
- Our San Diego New Year's Eve route is planned for Dec 30 – Jan 1, a window set by the holiday season rather than the weather — September falls outside it.
What to pack for September
- Light, breathable clotheshighs average 88°F
- Sunscreen, sunglasses and a hatstrong sun this month
- Refillable water bottleeasy to dehydrate in the heat
- Comfortable walking shoesmost picks involve some walking
What to do in Downtown San Diego & Gaslamp Quarter in September
Afternoons run hot (88°F), so these picks mix early-start outdoor spots with cool indoor breaks.
SeaWorld San Diego
Marine park on Mission Bay whose Christmas Celebration ends New Year's Eve with fireworks at about 9 pm.
Why now September scores 75/100 for comfort, good conditions for being outside.
Gaslamp Quarter
Sixteen blocks of Victorian-era buildings along Fifth Avenue, full of bars, clubs and restaurants.
USS Midway Museum
Aircraft carrier turned museum on the Navy Pier, with about 30 restored aircraft on the flight deck.
Why now A break from 88°F afternoons.
Hard Rock Hotel San Diego
Gaslamp hotel that throws one of the city's biggest New Year's Eve parties across several floors and its rooftop.
Why now Highs near 88°F and 0.2 in of monthly rain make this an easy outdoor pick.
Nearby in September
- La Jolla in September~11 mi · highs 76°F, 0.2 in rain · 6°C (11°F) cooler by day, about as wet
- Palm Springs in September~85 mi · highs 101°F, 0.2 in rain · 7°C (13°F) warmer by day, about as wet
- Joshua Tree in September~108 mi · highs 94°F, 0.2 in rain · 4°C (6°F) warmer by day, about as wet
- Los Angeles in September~112 mi · highs 88°F, 0.1 in rain · similar daytime temperatures, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid, temperatures adjusted from the grid cell's ~394 m to Downtown San Diego & Gaslamp Quarter's ~10 m elevation (standard lapse rate). Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Downtown San Diego & Gaslamp Quarter in September: quick answers
Is September a good time to visit Downtown San Diego & Gaslamp Quarter?
It's a good shoulder-season choice, scoring 75/100 against a best of 93 in October – March. Expect highs of 88°F (31°C) and 0.2 in (6 mm) of rain.
How hot is Downtown San Diego & Gaslamp Quarter in September?
Average highs are 88°F (31°C) and average lows 66°F (19°C), making it the 3rd-warmest month by daytime highs.
Does it rain a lot in Downtown San Diego & Gaslamp Quarter in September?
Not much: about 0.2 in (6 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 10.6 in (268 mm).
What should I pack for Downtown San Diego & Gaslamp Quarter in September?
Bring light, breathable clothes (highs average 88°F), sunscreen, sunglasses and a hat (strong sun this month), refillable water bottle (easy to dehydrate in the heat) and comfortable walking shoes (most picks involve some walking).
More on Downtown San Diego & Gaslamp Quarter
Planning Downtown San Diego & Gaslamp Quarter in September?
Bring the crew into one shared trip: vote on dates, build the day-by-day plan, split costs and share one packing list.