Location data · Baden-Württemberg
Sun hours in Heidelberg
How sunny is Heidelberg? Over a year the sun delivers 1,286 kilowatt-hours onto every square metre here — in June roughly 10 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 3.52 peak sun hours per day in Heidelberg. In 9 out of 10 years at least 1,181 kWh/m² are reached. All values are computed from this location’s satellite hourly data, not estimated.
- Annual average (PSH)
- 3.52 kWh/m²/d
- P90 annual total
- 1,181 kWh/m²
- Optimal tilt
- 35°
- Terrain horizon max.
- 16.8°
Sun hours per month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PSH/day (35° south) | 1.02 | 2.30 | 3.61 | 4.94 | 5.08 | 5.55 | 5.54 | 5.04 | 4.39 | 2.81 | 1.39 | 0.57 |
| P90 | 0.75 | 1.66 | 2.77 | 3.99 | 4.08 | 4.83 | 4.72 | 4.39 | 3.73 | 2.24 | 0.98 | 0.44 |
Daily average per month in kWh/m² at 35° tilt, south-facing, including the terrain horizon of Heidelberg. P90 = reached in 9 out of 10 years.
Optimal tilt angle in Heidelberg
The annual optimum for Heidelberg is 35° south; anything between 19° and 47° counts as equivalent (below 2% difference). For winter operation (off-grid) 60° is optimal, for summer use 20°. Flat-laid modules lose 11.4 % versus the optimum. Adjusting twice a year would add 1.9 % here, monthly adjustment 2.5 % — only relevant for adjustable mounts.
Is a balcony solar kit worth it in Heidelberg?
A vertical south-facing railing in Heidelberg harvests 875 kWh/m² per year — 68 % 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 76 % of the 35° December value, computed from the same hourly data with its own plane transposition. Open the balcony solar calculator with these coordinates →