India Solar Irradiance Map — Global Horizontal Irradiance

Annual average GHI (Global Horizontal Irradiance) in kWh/m²/day for any Indian city. Five tiers from Low (NE clouds < 4.5 kWh/m²/day) to Excellent (Rajasthan / Ladakh > 6.0). Drives PV system sizing, payback, ECBC daylighting credits, and solar water heating.
12
low
37
moderate
68
good
67
very-good
13
excellent
Low · < 4.5 kWh/m²/day · < 4.5 kWh/m²/day
Moderate · 4.5–5.0 kWh/m²/day · 4.5–5.0 kWh/m²/day
Good · 5.0–5.5 kWh/m²/day · 5.0–5.5 kWh/m²/day
Very Good · 5.5–6.0 kWh/m²/day · 5.5–6.0 kWh/m²/day
Excellent · > 6.0 kWh/m²/day · > 6.0 kWh/m²/day
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Click any spot on the map to drop a pin and get the estimated zone. Map data © OpenStreetMap contributors.

About PV system sizing

Annual energy = kWp × GHI × 365 × performance ratio (0.75-0.85). For 1 kWp in “Good” zone (GHI = 5.2 kWh/m²/day): 1 × 5.2 × 365 × 0.80 = ~1,520 kWh/year. Roof area required: ~7 m² per kWp (mono) or 9 m² (poly).

Payback: at ₹6/unit grid tariff and ₹50,000/kWp installed cost (after subsidy): ₹50,000 ÷ (1,520 × ₹6) = 5.5 years. Better in “Excellent” zones (4 years) and worse in “Low” zones (8+ years).

Practical implications

  • Excellent: Utility-scale solar parks economically viable. 320+ sunny days.
  • Very Good: Residential PV payback 3-5 years.
  • Good: Standard residential PV. Payback 5-7 years.
  • Moderate: PV viable with subsidy + net metering.
  • Low: Hybrid solar + wind/grid recommended. Standalone PV not economical.

Cross-references

Source IS / IRC / NBC standards

IS 16221 — Solar PVQuality + safety of PV modulesNBC 2016 + ECBCDaylighting + renewable energy credits

Related maps

Climate ZonesSunny climate zones = better PV economicsAir QualityHigh pollution reduces PV output 10-20%

Calculators & tools

Cost CalculatorPV system 50K/kWp installed

Articles & guides

CE HandbookRoof slope + orientation reference

Frequently asked questions

Where is the best solar in India?

Western Rajasthan (Jaisalmer, Bikaner, Jodhpur), Kutch (Gujarat), and Ladakh — all > 6 kWh/m²/day. Rajasthan hosts Bhadla Solar Park (2.25 GW), among the world's largest. Pavagada (Karnataka) at 2 GW also operates in 'Very Good' zone.

What is GHI vs DNI vs DHI?

GHI (Global Horizontal Irradiance) — total solar energy on horizontal surface = direct + diffuse. Used for fixed-tilt PV. DNI (Direct Normal Irradiance) — direct beam component, used for concentrated solar (CSP) tracking. DHI (Diffuse Horizontal Irradiance) — scattered sky radiation, important for cloudy regions and daylighting design.

What size PV system for a 3-bedroom home?

Average 3-BR home consumes 300-500 kWh/month. In 'Good' zone (5.0 kWh/m²/day GHI): 3-4 kWp covers ~75% of usage. Installed cost ₹1.5-2 lakh after subsidy. Roof area 25-30 m². Payback 4-5 years with net metering.

GHI values are 2005-2020 long-period averages from MNRE Solar Atlas + Solargis. Actual yield varies ±10% by year and ±5% by site (urban shading, soiling, panel orientation). Detailed simulation (PVsyst, NREL SAM) recommended for projects > 10 kWp.

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