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Solar and backup power in San Diego
San Diego, California, gets 4.91 peak sun hours a day on average. The dullest month is December at 2.92 hours, 52% less than April, the sunniest at 6.14. That makes it sunnier than 79% of the 104 cities we cover in the United States.
Sunshine in San Diego is clearly below its yearly average for 4 months, from November to February. That stretch decides how many panels you need if solar has to keep up all year. Across the year, San Diego gets 11% more sunshine than the average of the cities we cover in the United States.
What a home in San Diego needs
Three example homes, each covering a 12-hour daily outage with a lithium battery and solar panels to recharge it. Panels are 450 W. The month-with-least-sun figure is what keeps you covered all year.
| Home | Inverter | Battery | Panels, December | Panels, yearly average |
|---|---|---|---|---|
| Essentials 6 lights, 2 fans, a fridge, TV, Wi-Fi and phone charging | 1 kW | 2.6 kWh | 3 | 2 |
| Family home Essentials plus a freezer, more lights, a laptop, a desktop and a water pump | 3 kW | 7.4 kWh | 6 | 4 |
| With air conditioning The family home plus two small air conditioners for 6 hours a day | 5 kW | 14.9 kWh | 13 | 8 |
Your own appliances will differ. Put them into the calculator below, which already has San Diego's sunshine.
Size your own system in San Diego
Planning tips for San Diego
- Size panels for December, not for the yearly average. A system sized on the average falls short in the dullest weeks, which is when you most need it.
- Dust, heat and shade cut output. Keep panels clean, leave air space under them, and avoid anything that shades them between mid-morning and mid-afternoon.
- Ask installers for the inverter's continuous and surge ratings, the battery's usable capacity and chemistry, and the panels' total watts. Compare those numbers with your plan rather than the package name.
Guides for planning in San Diego
- Peak sun hours and your dullest month
- How many solar panels you need
- Lithium vs lead-acid batteries
- Questions to ask an installer
Nearby cities
- Irvine 122 km · 5.42 h
- Riverside 139 km · 5.42 h
- Long Beach 151 km · 5.04 h
- Los Angeles 179 km · 5.65 h
- Bakersfield 341 km · 5.58 h
- Las Vegas 427 km · 5.61 h
All cities in the United States
Sunshine: NASA POWER climatology, ALLSKY_SFC_SW_DWN, monthly averages for 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025), at 32.7157, -117.1647; retrieved 2026-11-09. Peak sun hours equal kWh of sunlight per square metre per day on flat ground; tilted panels usually collect a little more.