Peak Sun Hours in Fresno, California, United States
- Solar zone
- Zone 4 (excellent)
- Best month
- June (8.5)
- Worst month
- December (2.2)
- Climate
- Temperate · 18.7°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 2.44 | 3.45 | 3.81 | 1.03 | 9.5 | 73 |
| Feb | 3.59 | 4.58 | 5.10 | 1.26 | 10.7 | 73 |
| Mar | 5.07 | 6.04 | 6.22 | 1.62 | 13.3 | 69 |
| Apr | 6.46 | 7.43 | 7.38 | 1.81 | 16.0 | 60 |
| May | 7.66 | 8.32 | 8.89 | 1.69 | 21.1 | 46 |
| Jun | 8.46 | 8.72 | 10.52 | 1.31 | 26.4 | 32 |
| Jul | 8.11 | 8.36 | 9.95 | 1.33 | 30.2 | 26 |
| Aug | 7.42 | 7.61 | 9.51 | 1.21 | 28.8 | 29 |
| Sep | 6.14 | 6.36 | 8.55 | 1.08 | 25.7 | 33 |
| Oct | 4.54 | 4.94 | 7.04 | 1.03 | 19.7 | 43 |
| Nov | 3.07 | 3.69 | 5.21 | 0.96 | 13.5 | 59 |
| Dec | 2.24 | 3.09 | 3.80 | 0.91 | 9.1 | 71 |
GHI, Clear-sky, DNI, DHI in kWh/m²/day. Data: NASA POWER climatology (long-term monthly averages).
Off-grid calculator
Add appliances
- Add an appliance to size a system.
Sizing
- Daily load
- 0.00 kWh
- Panel wattage
- 0 W
- Panel count (400W modules)
- 0
- Battery bank
- 0.0 kWh
Sizing against worst-month PSH of 2.24 kWh/m²/day, 0.77 system efficiency.
About solar in Fresno
Fresno, United States has a temperate climate with meaningful seasonal variation in solar resource. Its annual peak sun hours average 5.43 kWh/m²/day, a excellent solar resource by global standards.
The strongest month in Fresno is June (summer) at 8.46 kWh/m²/day, and the weakest is December (winter) at 2.24 kWh/m²/day. When sizing a year-round off-grid system, it's standard practice to design against the December value rather than the annual average — otherwise the battery bank runs low during the darkest weeks.
Fresno's solar conditions are well within the range where off-grid PV is a straightforward engineering exercise with standard-sized arrays and lithium batteries.
FAQ
- What are the peak sun hours in Fresno?
- Fresno averages 5.43 peak sun hours per day annually, ranging from 2.24 in December to 8.46 in June.
- How many solar panels do I need in Fresno?
- Panel count depends on your daily load. At Fresno's annual average of 5.43 kWh/m²/day, a 5 kWh/day load needs roughly 3 × 400 W panels. Use the calculator above for your actual load.
- What size battery do I need in Fresno?
- Sizing against Fresno's worst month (December, 2.24 kWh/m²/day) with 2 days of autonomy at 80% depth of discharge, a 5 kWh/day load needs about a 12.5 kWh battery bank.
- How does Fresno's solar resource compare globally?
- Fresno sits in solar zone 4 out of 5 (where 5 is strongest) at 5.43 kWh/m²/day — excellent by global standards. For reference, top-tier desert sites average ~6.5 and high-latitude cities around 2.5 kWh/m²/day.
- How much does winter reduce solar output in Fresno?
- Fresno's worst month (December) delivers 2.24 kWh/m²/day — about 26% of the summer peak of 8.46. Off-grid systems here typically oversize 1.5–2× or pair with a backup source.
- Do cloudy days significantly affect Fresno's solar?
- Partly. Diffuse light still produces 10–25% of clear-sky output. Fresno's 5.43 kWh/m²/day already reflects average cloudiness, so no further derating is needed for sizing.
- What panel tilt works best in Fresno?
- At Fresno's latitude (37°), a fixed tilt near 37° balances year-round yield. Winter-heavy loads favor latitude + 15°; summer-heavy, latitude − 15°.