Solar Panel Tilt Angle Calculator | Find the Best Tilt & Direction

Monthly Temperature Trends

Red is the daytime high and blue the night-time low for each month at your location.

Daily high and low temperature averages by month from the last 5 complete years of historical data. Temperature directly affects solar panel efficiency - panels lose approximately 0.35% efficiency per degree Celsius above 25°C, and run slightly better below 25°C. Hotter months (red line) reduce voltage and power output, while cooler months improve performance.

Very hot summers mean slightly less production on the hottest days - a small, expected dip, not a problem.

Seasonal Sun Path - Solar Elevation at Noon

How high the sun climbs at noon in each month - higher sun means stronger production.

Solar elevation angle at solar noon throughout the year, calculated using monthly declination angles at your latitude. Points are color-coded: red (high sun >60°), amber (moderate 30-60°), and blue (low sun <30°). Higher sun angles produce more energy per panel area and allow flatter tilt angles for better summer yield.

The gap between the highest and lowest dots shows how much your production will swing between summer and winter.

Tilt Angle Comparison

Three ways to angle your panels: one angle all year, a flatter summer angle, or a steeper winter angle.

Recommended panel tilt angles for your latitude. Fixed tilt (green) is the recommended year-round angle - about 87% of your absolute latitude, the same rule the Energy Yield tool uses. Summer tilt (amber) is 10° flatter to capture high-angle sun, while winter tilt (blue) is 10° steeper for low-angle collection. Seasonal tilt adjustments can boost annual yield by a few percent in regions with pronounced seasonal variation.

If the three bars are close together, adjusting the tilt twice a year isn't worth it - a fixed mount is fine.

Sunlight & Daylight Hours

Amber bars are the average sunlight your roof receives each month (kWh per m² per day); the blue line is how many hours of daylight that month has.

Sunlight (insolation) is the 5-year monthly average of horizontal-surface irradiation from the Open-Meteo archive. Daylight hours come from your latitude via the sunrise/sunset cosine law. Longer summer days plus higher sun angles are exactly why solar output peaks in the warmer months: the production band your latitude maps to (145/135/110/85 kWh per kWp per month) assumes this seasonal shape.

If the amber bars stay high most of the year, your site is a strong solar candidate - a flatter fixed tilt is fine. If they dip hard in winter, plan for a steeper cold-season angle.