Peak Sun Hours in Cergy-Pontoise, Île-de-France, France
- Solar zone
- Zone 2 (moderate)
- Best month
- June (5.6)
- Worst month
- December (0.7)
- Climate
- Temperate · 10.7°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 0.91 | 1.63 | 1.54 | 0.54 | 3.1 | 93 |
| Feb | 1.64 | 2.75 | 2.24 | 0.89 | 3.7 | 88 |
| Mar | 2.88 | 4.36 | 2.93 | 1.50 | 6.5 | 83 |
| Apr | 4.45 | 6.14 | 3.99 | 2.17 | 10.0 | 78 |
| May | 5.16 | 7.46 | 3.89 | 2.65 | 13.4 | 78 |
| Jun | 5.63 | 7.97 | 4.01 | 2.93 | 16.9 | 76 |
| Jul | 5.43 | 7.59 | 3.94 | 2.81 | 18.9 | 73 |
| Aug | 4.60 | 6.41 | 3.73 | 2.34 | 18.5 | 74 |
| Sep | 3.58 | 4.91 | 3.79 | 1.69 | 15.4 | 77 |
| Oct | 2.11 | 3.18 | 2.64 | 1.10 | 11.5 | 85 |
| Nov | 1.08 | 1.87 | 1.72 | 0.62 | 7.0 | 91 |
| Dec | 0.73 | 1.32 | 1.44 | 0.42 | 3.6 | 93 |
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 0.73 kWh/m²/day, 0.77 system efficiency.
About solar in Cergy-Pontoise
Cergy-Pontoise, France has a temperate climate with meaningful seasonal variation in solar resource. Its annual peak sun hours average 3.18 kWh/m²/day, a moderate solar resource by global standards.
The strongest month in Cergy-Pontoise is June (summer) at 5.63 kWh/m²/day, and the weakest is December (winter) at 0.73 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.
Given the moderate resource, Cergy-Pontoise installations typically oversize panels or combine solar with another source (grid, generator, hydro) for reliability.
FAQ
- What are the peak sun hours in Cergy-Pontoise?
- Cergy-Pontoise averages 3.18 peak sun hours per day annually, ranging from 0.73 in December to 5.63 in June.
- How many solar panels do I need in Cergy-Pontoise?
- Panel count depends on your daily load. At Cergy-Pontoise's annual average of 3.18 kWh/m²/day, a 5 kWh/day load needs roughly 6 × 400 W panels. Use the calculator above for your actual load.
- What size battery do I need in Cergy-Pontoise?
- Sizing against Cergy-Pontoise's worst month (December, 0.73 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 Cergy-Pontoise's solar resource compare globally?
- Cergy-Pontoise sits in solar zone 2 out of 5 (where 5 is strongest) at 3.18 kWh/m²/day — moderate 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 Cergy-Pontoise?
- Cergy-Pontoise's worst month (December) delivers 0.73 kWh/m²/day — about 13% of the summer peak of 5.63. Off-grid systems here typically oversize 1.5–2× or pair with a backup source.
- Do cloudy days significantly affect Cergy-Pontoise's solar?
- Partly. Diffuse light still produces 10–25% of clear-sky output. Cergy-Pontoise's 3.18 kWh/m²/day already reflects average cloudiness, so no further derating is needed for sizing.
- What panel tilt works best in Cergy-Pontoise?
- At Cergy-Pontoise's latitude (49°), a fixed tilt near 49° balances year-round yield. Winter-heavy loads favor latitude + 15°; summer-heavy, latitude − 15°.