Peak Sun Hours in Patna, Bihar, India
- Solar zone
- Zone 3 (good)
- Best month
- April (6.4)
- Worst month
- December (3.1)
- Climate
- Tropical · 26.2°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 3.19 | 3.80 | 2.69 | 1.60 | 15.6 | 51 |
| Feb | 4.47 | 4.85 | 4.17 | 1.79 | 20.0 | 44 |
| Mar | 5.70 | 6.02 | 5.15 | 2.04 | 26.2 | 31 |
| Apr | 6.38 | 6.74 | 5.04 | 2.43 | 32.2 | 26 |
| May | 6.36 | 6.91 | 4.33 | 2.72 | 35.0 | 34 |
| Jun | 5.49 | 6.76 | 2.76 | 2.92 | 34.6 | 50 |
| Jul | 4.59 | 6.79 | 1.87 | 2.74 | 30.4 | 77 |
| Aug | 4.86 | 6.61 | 2.47 | 2.68 | 29.2 | 83 |
| Sep | 4.65 | 5.97 | 2.74 | 2.43 | 28.0 | 84 |
| Oct | 4.60 | 5.17 | 4.08 | 1.85 | 25.5 | 74 |
| Nov | 3.97 | 4.12 | 4.09 | 1.56 | 20.9 | 64 |
| Dec | 3.11 | 3.49 | 2.98 | 1.45 | 16.5 | 58 |
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 3.11 kWh/m²/day, 0.77 system efficiency.
About solar in Patna
Patna, India has a warm, tropical climate with a distinct wet and dry season. Its annual peak sun hours average 4.78 kWh/m²/day, a good solar resource by global standards.
The strongest month in Patna is April (spring) at 6.38 kWh/m²/day, and the weakest is December (winter) at 3.11 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.
Patna'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 Patna?
- Patna averages 4.78 peak sun hours per day annually, ranging from 3.11 in December to 6.38 in April.
- How many solar panels do I need in Patna?
- Panel count depends on your daily load. At Patna's annual average of 4.78 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 Patna?
- Sizing against Patna's worst month (December, 3.11 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 Patna's solar resource compare globally?
- Patna sits in solar zone 3 out of 5 (where 5 is strongest) at 4.78 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 Patna?
- Patna's dry-season output peaks at 6.38 kWh/m²/day in April; the wet season drops it to 3.11 in December. That ~68% swing is a key sizing consideration.
- Can solar panels survive tropical storms in Patna?
- 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 Patna?
- Patna swings from 6.38 kWh/m²/day in April (dry) to 3.11 in December (wet) — roughly 68%. Year-round off-grid systems must size against the wet-season minimum.