Location data · Baden-Württemberg
Sun hours in Calw
How sunny is Calw? Over a year the sun delivers 1,412 kilowatt-hours onto every square metre here — in June roughly 4 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 3.87 peak sun hours per day in Calw. In 9 out of 10 years at least 1,324 kWh/m² are reached. All values are computed from this location’s satellite hourly data, not estimated.
- Annual average (PSH)
- 3.87 kWh/m²/d
- P90 annual total
- 1,324 kWh/m²
- Optimal tilt
- 35°
- Terrain horizon max.
- 7.6°
Sun hours per month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PSH/day (35° south) | 1.64 | 2.71 | 3.98 | 5.01 | 5.12 | 5.66 | 5.61 | 5.15 | 4.57 | 3.23 | 2.09 | 1.59 |
| P90 | 1.24 | 1.96 | 3.00 | 4.04 | 4.46 | 4.85 | 4.89 | 4.47 | 3.98 | 2.65 | 1.64 | 1.16 |
Daily average per month in kWh/m² at 35° tilt, south-facing, including the terrain horizon of Calw. P90 = reached in 9 out of 10 years.
Optimal tilt angle in Calw
The annual optimum for Calw is 35° south; anything between 23° and 50° counts as equivalent (below 2% difference). For winter operation (off-grid) 65° is optimal, for summer use 20°. Flat-laid modules lose 14.3 % versus the optimum. Adjusting twice a year would add 2.8 % here, monthly adjustment 3.6 % — only relevant for adjustable mounts.
Is a balcony solar kit worth it in Calw?
A vertical south-facing railing in Calw harvests 996 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 →
Neighbouring places compared
- Herrenberg4.00 kWh/m²/d16 km
- Pforzheim3.91 kWh/m²/d19 km
- Sindelfingen3.85 kWh/m²/d20 km