Solar panels in Singapore produce almost 60% more electricity per kWp than panels in London, despite being at nearly identical tilt angles. The difference is not the hardware — it is the location. Solar resource varies enormously across the globe, and understanding how your location affects yield is essential for proper system sizing and financial planning.
Specific Yield by City
The table below shows the estimated annual specific yield (kWh per installed kWp) for 20 global cities. These values assume a south-facing array at optimal tilt, with standard system losses of 14% and no shading.
| City | Latitude | Climate Zone | Annual GHI (kWh/m²) | Specific Yield (kWh/kWp) |
|---|---|---|---|---|
| Singapore | 1°N | Tropical rainforest | 1,720 | 1,480 |
| Mumbai, India | 19°N | Tropical monsoon | 1,900 | 1,580 |
| Dubai, UAE | 25°N | Arid desert | 2,100 | 1,650 |
| Houston, USA | 30°N | Humid subtropical | 1,770 | 1,450 |
| Shanghai, China | 31°N | Humid subtropical | 1,580 | 1,300 |
| Lahore, Pakistan | 31°N | Semi-arid | 1,860 | 1,520 |
| Sydney, Australia | 34°S | Subtropical | 1,740 | 1,400 |
| Cape Town, South Africa | 34°S | Mediterranean | 1,900 | 1,520 |
| Tokyo, Japan | 36°N | Humid subtropical | 1,480 | 1,200 |
| Madrid, Spain | 40°N | Mediterranean | 1,880 | 1,500 |
| Phoenix, USA | 33°N | Arid desert | 2,000 | 1,620 |
| Los Angeles, USA | 34°N | Mediterranean | 1,880 | 1,500 |
| Milan, Italy | 45°N | Humid subtropical | 1,550 | 1,250 |
| Toronto, Canada | 44°N | Cold continental | 1,390 | 1,100 |
| London, UK | 51°N | Maritime temperate | 1,200 | 950 |
| Berlin, Germany | 53°N | Temperate continental | 1,150 | 900 |
| Amsterdam, Netherlands | 52°N | Maritime temperate | 1,130 | 910 |
| Paris, France | 49°N | Temperate oceanic | 1,240 | 1,000 |
| Seoul, South Korea | 37°N | Continental | 1,450 | 1,180 |
| Melbourne, Australia | 38°S | Subtropical | 1,620 | 1,320 |
Why Location Matters: Key Factors
1. Global Horizontal Irradiance (GHI)
GHI is the total solar radiation received per square meter on a horizontal surface. It is the single biggest factor in solar yield. The GHI range globally is roughly 900-2,500 kWh/m²/year. Higher GHI means more sunlight available for conversion.
2. Temperature Coefficient Loss
Solar panels have a negative temperature coefficient: efficiency drops as temperature rises. Most crystalline silicon panels lose 0.25-0.35% per °C above 25°C (STC). In hot climates like Dubai, Phoenix, and Mumbai, panel temperatures on the roof can reach 65-75°C during peak sun, leading to annual temperature-related losses of 8-12%.
3. Air Mass (AM)
Air mass describes the path length of sunlight through the atmosphere. At sea level near the equator (sun directly overhead), AM = 1. At higher latitudes or lower sun angles, AM increases, meaning more atmosphere for light to travel through, reducing irradiance. This is why the same panel at 50° latitude receives less effective sunlight even on a clear day.
4. Cloud Cover and Weather Patterns
Cloud cover is the dominant cause of yield variation within a given latitude band. Maritime climates (London, Amsterdam) have 60-70% average cloud cover, while arid climates (Dubai, Phoenix) have 15-25%. This single factor explains most of the yield gap between similar-latitude cities.
The Yield Formula
System efficiency accounts for all losses combined: inverter conversion (96-98%), wiring losses (1-2%), temperature derating (varies), soiling (2-5%), mismatch (1-2%), and degradation (0.3-0.5%/yr). A typical system efficiency is 75-82%.
Example for Dubai: GHI 2,100 kWh/m² × 78% efficiency = 1,638 kWh/kWp (close to the 1,650 in our table). Example for London: GHI 1,200 kWh/m² × 79% efficiency = 948 kWh/kWp (close to the 950 value).
Temperature Derating in Detail
The temperature coefficient is often overlooked but can significantly affect system output, especially in hot climates. The derating formula per hour is:
Where Tc is the temperature coefficient (e.g., -0.0030 for -0.30%/°C) and T_cell is the actual cell temperature. Cell temperature on a roof can be 25-35°C above ambient air temperature due to the panel's dark surface absorbing heat.
| Location | Avg Peak Temp (°C) | Estimated Temp Loss |
|---|---|---|
| Dubai, UAE | 45 | 10.5% |
| Phoenix, USA | 44 | 10.2% |
| Mumbai, India | 38 | 7.8% |
| Los Angeles, USA | 30 | 4.5% |
| London, UK | 22 | 0.0% |
| Berlin, Germany | 24 | 0.9% |
Using Location Data for System Sizing
To size a system using location-specific yield data:
- Find your city's specific yield from the table above (or use PVGIS for your exact location).
- Divide your annual kWh target by the specific yield to get kWp required.
- Apply a 5-10% buffer for P90 confidence (see our P50 vs P90 guide).
Example: A home in Mumbai targeting 8,000 kWh/year would need 8,000 ÷ 1,580 = 5.1 → 5.5 kWp system.
Related Guides
- Best Solar Panel Angle and Direction for Max Yield
- Solar Panel Performance in Winter vs Summer
- Solar P50 vs P90 Yield: Why Banks Require P90
See what your location can produce
Open the Solar Calculator →Data sources: NASA POWER (2025), Solargis, PVGIS 5.2, NREL PVWatts v8. Specific yield values are estimates for optimally-oriented systems with 14% total system losses. Actual yield depends on site-specific conditions including shading, soiling, and equipment selection.
Last updated: July 2026 | Browse all guides