San Diego in December
In December, San Diego averages 18°C (64°F) during the day and 9°C (48°F) at night, with around 8 days of rain (63 mm total).
High seasonConditions are cool — bring a jacket for evenings. Occasional showers are likely but won't dominate.
December in San Diego is outside the typical sweet spot for sightseeing weather. It can still be a great time to visit if you have specific reasons (festivals, off-season pricing, etc.).
How December compares to the rest of the year in San Diego
December is one of the coolest months in San Diego (12th of 12) and moderately rainy compared to the rest of the year (6th of 12). Daytime temperature runs 4°C below the annual average (21°C). December runs 3°C cooler than November (21°C) and stays flat into January.
December sunrise & sunset in San Diego
Times shown for San Diego local time (America/Los_Angeles), calculated for the 15th of December. They shift by a few minutes day to day across the month.
Photography light in San Diego — December
Golden-hour and blue-hour windows for the 15th of December, in San Diego's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — San Diego in December
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on December's tier (High season) and San Diego's popularity.
December in United States — events that affect travel
Known cultural, religious, or national events that surge prices, fill hotels, or close businesses during this month. Plan around them, or build your itinerary around the ones you'd like to see.
Major travel surge plus widespread Dec 24-26 and Jan 1 business closures.
Plan: Book flights and hotels well ahead; expect many restaurants/shops closed Dec 25 and Jan 1.
Crowds & pricing — December in San Diego
This is a busy month in San Diego — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: comfortable tourism weather Christmas / New Year travel surge
Sun & mosquito risk — December in San Diego
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Sea temperature in San Diego — December
Across the year San Diego's sea swings from 14.7°C (February) to 21.5°C (August) — December sits at 15.6°C.
San Diego in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 18°C / 64°F | 9°C / 48°F | 62 mm | 8 | — |
| February | 18°C / 65°F | 9°C / 48°F | 48 mm | 8 | — |
| March | 19°C / 65°F | 11°C / 51°F | 44 mm | 11 | — |
| April | 20°C / 68°F | 13°C / 55°F | 22 mm | 8 | — |
| May | 20°C / 68°F | 14°C / 58°F | 16 mm | 9 | — |
| June | 22°C / 72°F | 16°C / 61°F | 2 mm | 4 | — |
| July | 25°C / 76°F | 18°C / 65°F | 5 mm | 2 | — |
| August | 26°C / 78°F | 19°C / 66°F | 9 mm | 3 | — |
| September | 26°C / 78°F | 18°C / 65°F | 11 mm | 5 | — |
| October | 24°C / 76°F | 16°C / 60°F | 10 mm | 5 | — |
| November | 21°C / 70°F | 12°C / 53°F | 28 mm | 6 | — |
| December | 18°C / 64°F | 9°C / 48°F | 63 mm | 8 | — |
Other cities with similar December weather
🌍 See the full ranked list of climate twins for San Diego in December →
Frequently asked questions
How hot is San Diego in December?
In December, San Diego averages a high of 18°C (64°F) and a low of 9°C (48°F) — generally mild and pleasant.
Does it rain a lot in San Diego in December?
December sees occasional rain in San Diego, with about 8 rainy days on average.
Is December a good time to visit San Diego?
December is mild and pleasant. It suits travelers who are comfortable with mild and pleasant weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for San Diego in December?
Pack light layers for warm days and cooler evenings. See the full December packing list for San Diego for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.