Peak Sun Hours in Kolkata, West Bengal, India
- Solar zone
- Zone 3 (good)
- Best month
- April (5.9)
- Worst month
- December (3.5)
- Climate
- Tropical · 25.8°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 3.78 | 4.08 | 3.28 | 1.72 | 17.3 | 65 |
| Feb | 4.69 | 5.01 | 4.04 | 1.94 | 22.0 | 57 |
| Mar | 5.41 | 5.84 | 3.97 | 2.34 | 27.4 | 55 |
| Apr | 5.93 | 6.55 | 3.84 | 2.68 | 31.2 | 60 |
| May | 5.76 | 6.76 | 3.14 | 2.91 | 31.5 | 67 |
| Jun | 4.55 | 6.69 | 1.63 | 2.84 | 29.9 | 80 |
| Jul | 4.20 | 6.91 | 1.22 | 2.82 | 28.7 | 87 |
| Aug | 4.21 | 6.67 | 1.39 | 2.78 | 28.2 | 89 |
| Sep | 4.35 | 6.10 | 2.04 | 2.56 | 27.7 | 89 |
| Oct | 4.36 | 5.33 | 3.13 | 2.07 | 26.0 | 84 |
| Nov | 4.11 | 4.43 | 3.87 | 1.70 | 21.9 | 78 |
| Dec | 3.55 | 3.83 | 3.32 | 1.59 | 17.8 | 74 |
GHI, Clear-sky, DNI, DHI in kWh/m²/day. Data: NASA POWER climatology (long-term monthly averages).
Off-grid calculator
Add appliances
- Add an appliance to size a system.
Sizing
- Daily load
- 0.00 kWh
- Panel wattage
- 0 W
- Panel count (400W modules)
- 0
- Battery bank
- 0.0 kWh
Sizing against worst-month PSH of 3.55 kWh/m²/day, 0.77 system efficiency.
About solar in Kolkata
Kolkata, India has a warm, tropical climate with a distinct wet and dry season. Its annual peak sun hours average 4.58 kWh/m²/day, a good solar resource by global standards.
The strongest month in Kolkata is April (spring) at 5.93 kWh/m²/day, and the weakest is December (winter) at 3.55 kWh/m²/day. When sizing a year-round off-grid system, it's standard practice to design against the December value rather than the annual average — otherwise the battery bank runs low during the darkest weeks.
Kolkata's solar conditions are well within the range where off-grid PV is a straightforward engineering exercise with standard-sized arrays and lithium batteries.
FAQ
- What are the peak sun hours in Kolkata?
- Kolkata averages 4.58 peak sun hours per day annually, ranging from 3.55 in December to 5.93 in April.
- How many solar panels do I need in Kolkata?
- Panel count depends on your daily load. At Kolkata's annual average of 4.58 kWh/m²/day, a 5 kWh/day load needs roughly 4 × 400 W panels. Use the calculator above for your actual load.
- What size battery do I need in Kolkata?
- Sizing against Kolkata's worst month (December, 3.55 kWh/m²/day) with 2 days of autonomy at 80% depth of discharge, a 5 kWh/day load needs about a 12.5 kWh battery bank.
- How does Kolkata's solar resource compare globally?
- Kolkata sits in solar zone 3 out of 5 (where 5 is strongest) at 4.58 kWh/m²/day — good by global standards. For reference, top-tier desert sites average ~6.5 and high-latitude cities around 2.5 kWh/m²/day.
- How does the wet season affect solar generation in Kolkata?
- Kolkata's dry-season output peaks at 5.93 kWh/m²/day in April; the wet season drops it to 3.55 in December. That ~52% swing is a key sizing consideration.
- Can solar panels survive tropical storms in Kolkata?
- Most tier-1 PV panels are rated for 140+ mph wind loads; mounting hardware usually fails first. In cyclone-prone regions like India, specify IEC 61215-certified panels and anchor-bolt mounts rather than ballasted.
- What's the dry-to-wet output gap in Kolkata?
- Kolkata swings from 5.93 kWh/m²/day in April (dry) to 3.55 in December (wet) — roughly 52%. Year-round off-grid systems must size against the wet-season minimum.