Peak Sun Hours in Haikou, Hainan, China
- Solar zone
- Zone 3 (good)
- Best month
- July (5.6)
- Worst month
- January (2.8)
- Climate
- Tropical · 24.7°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 2.82 | 4.64 | 1.98 | 1.59 | 18.8 | 83 |
| Feb | 3.33 | 5.37 | 2.07 | 1.84 | 20.0 | 85 |
| Mar | 3.86 | 5.81 | 1.97 | 2.17 | 22.4 | 84 |
| Apr | 4.66 | 6.49 | 2.58 | 2.42 | 25.3 | 83 |
| May | 5.45 | 7.14 | 3.57 | 2.55 | 27.6 | 85 |
| Jun | 5.49 | 7.30 | 3.40 | 2.77 | 28.4 | 87 |
| Jul | 5.58 | 7.33 | 3.72 | 2.65 | 28.4 | 87 |
| Aug | 5.14 | 7.04 | 3.31 | 2.48 | 28.2 | 87 |
| Sep | 4.72 | 6.45 | 3.00 | 2.38 | 27.7 | 85 |
| Oct | 4.16 | 5.53 | 2.88 | 2.07 | 25.9 | 83 |
| Nov | 3.50 | 4.85 | 2.88 | 1.71 | 23.5 | 82 |
| Dec | 2.86 | 4.33 | 2.24 | 1.52 | 20.1 | 81 |
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 2.82 kWh/m²/day, 0.77 system efficiency.
About solar in Haikou
Haikou, China has a warm, tropical climate with a distinct wet and dry season. Its annual peak sun hours average 4.3 kWh/m²/day, a good solar resource by global standards.
The strongest month in Haikou is July (summer) at 5.58 kWh/m²/day, and the weakest is January (winter) at 2.82 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.
Haikou'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 Haikou?
- Haikou averages 4.3 peak sun hours per day annually, ranging from 2.82 in January to 5.58 in July.
- How many solar panels do I need in Haikou?
- Panel count depends on your daily load. At Haikou's annual average of 4.3 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 Haikou?
- Sizing against Haikou's worst month (January, 2.82 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 Haikou's solar resource compare globally?
- Haikou sits in solar zone 3 out of 5 (where 5 is strongest) at 4.3 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 Haikou?
- Haikou's dry-season output peaks at 5.58 kWh/m²/day in July; the wet season drops it to 2.82 in January. That ~64% swing is a key sizing consideration.
- Can solar panels survive tropical storms in Haikou?
- Most tier-1 PV panels are rated for 140+ mph wind loads; mounting hardware usually fails first. In cyclone-prone regions like China, specify IEC 61215-certified panels and anchor-bolt mounts rather than ballasted.
- What's the dry-to-wet output gap in Haikou?
- Haikou swings from 5.58 kWh/m²/day in July (dry) to 2.82 in January (wet) — roughly 64%. Year-round off-grid systems must size against the wet-season minimum.