Peak Sun Hours in Cầu Giấy, Hanoi, Vietnam
- Solar zone
- Zone 2 (moderate)
- Best month
- June (5.0)
- Worst month
- January (2.2)
- Climate
- Tropical · 23.3°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 2.24 | 4.55 | 1.25 | 1.45 | 15.4 | 81 |
| Feb | 2.65 | 5.17 | 1.16 | 1.76 | 18.2 | 80 |
| Mar | 2.97 | 5.55 | 0.81 | 2.09 | 21.4 | 80 |
| Apr | 3.76 | 6.37 | 1.29 | 2.46 | 25.1 | 78 |
| May | 4.74 | 7.14 | 2.29 | 2.72 | 27.5 | 80 |
| Jun | 4.95 | 7.26 | 2.16 | 3.03 | 28.5 | 84 |
| Jul | 4.83 | 7.31 | 2.30 | 2.86 | 28.4 | 85 |
| Aug | 4.68 | 7.01 | 2.32 | 2.70 | 27.9 | 86 |
| Sep | 4.50 | 6.41 | 2.56 | 2.47 | 26.7 | 85 |
| Oct | 3.76 | 5.39 | 2.32 | 2.05 | 23.8 | 84 |
| Nov | 3.24 | 4.78 | 2.64 | 1.62 | 20.3 | 82 |
| Dec | 2.54 | 4.22 | 1.94 | 1.40 | 16.0 | 80 |
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 2.24 kWh/m²/day, 0.77 system efficiency.
About solar in Cầu Giấy
Cầu Giấy, Vietnam has a warm, tropical climate with a distinct wet and dry season. Its annual peak sun hours average 3.74 kWh/m²/day, a moderate solar resource by global standards.
The strongest month in Cầu Giấy is June (summer) at 4.95 kWh/m²/day, and the weakest is January (winter) at 2.24 kWh/m²/day. When sizing a year-round off-grid system, it's standard practice to design against the January value rather than the annual average — otherwise the battery bank runs low during the darkest weeks.
Given the moderate resource, Cầu Giấy installations typically oversize panels or combine solar with another source (grid, generator, hydro) for reliability.
FAQ
- What are the peak sun hours in Cầu Giấy?
- Cầu Giấy averages 3.74 peak sun hours per day annually, ranging from 2.24 in January to 4.95 in June.
- How many solar panels do I need in Cầu Giấy?
- Panel count depends on your daily load. At Cầu Giấy's annual average of 3.74 kWh/m²/day, a 5 kWh/day load needs roughly 5 × 400 W panels. Use the calculator above for your actual load.
- What size battery do I need in Cầu Giấy?
- Sizing against Cầu Giấy's worst month (January, 2.24 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 Cầu Giấy's solar resource compare globally?
- Cầu Giấy sits in solar zone 2 out of 5 (where 5 is strongest) at 3.74 kWh/m²/day — moderate 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 Cầu Giấy?
- Cầu Giấy's dry-season output peaks at 4.95 kWh/m²/day in June; the wet season drops it to 2.24 in January. That ~72% swing is a key sizing consideration.
- Can solar panels survive tropical storms in Cầu Giấy?
- Most tier-1 PV panels are rated for 140+ mph wind loads; mounting hardware usually fails first. In cyclone-prone regions like Vietnam, specify IEC 61215-certified panels and anchor-bolt mounts rather than ballasted.
- What's the dry-to-wet output gap in Cầu Giấy?
- Cầu Giấy swings from 4.95 kWh/m²/day in June (dry) to 2.24 in January (wet) — roughly 72%. Year-round off-grid systems must size against the wet-season minimum.