Location data · Geneva
Sun hours in Genf
How sunny is Genf? Over a year the sun delivers 1,594 kilowatt-hours onto every square metre here — in June roughly 3 times as much per day as in December. “Sun hours” has two meanings: the weather report counts how long the sun shines. For solar power what matters is how much energy arrives — and that is what this page shows, as peak sun hours (hours of full sun power).
For solar planning this means: an optimally tilted, south-facing array (35°) harvests an annual average of 4.37 peak sun hours per day in Genf. In 9 out of 10 years at least 1,503 kWh/m² are reached. All values are computed from this location’s satellite hourly data, not estimated.
- Annual average (PSH)
- 4.37 kWh/m²/d
- P90 annual total
- 1,503 kWh/m²
- Optimal tilt
- 40°
- Terrain horizon max.
- 6.9°
Sun hours per month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PSH/day (35° south) | 2.49 | 3.55 | 4.49 | 5.30 | 5.32 | 6.00 | 6.19 | 5.77 | 5.09 | 3.71 | 2.39 | 2.06 |
| P90 | 1.82 | 2.70 | 3.43 | 4.22 | 4.70 | 5.23 | 5.48 | 5.13 | 4.59 | 2.98 | 1.85 | 1.52 |
Daily average per month in kWh/m² at 35° tilt, south-facing, including the terrain horizon of Genf. P90 = reached in 9 out of 10 years.
Optimal tilt angle in Genf
The annual optimum for Genf is 40° south; anything between 25° and 51° counts as equivalent (below 2% difference). For winter operation (off-grid) 65° is optimal, for summer use 20°. Flat-laid modules lose 16.6 % versus the optimum. Adjusting twice a year would add 3.5 % here, monthly adjustment 4.5 % — only relevant for adjustable mounts.
Is a balcony solar kit worth it in Genf?
A vertical south-facing railing in Genf harvests 1,128 kWh/m² per year — 71 % of what an optimally tilted 35° panel yields at the same spot. December softens the penalty: with the low winter sun, the vertical plane reaches 108 % of the 35° December value, computed from the same hourly data with its own plane transposition. Open the balcony solar calculator with these coordinates →