Peak Sun Hours in Raleigh, North Carolina, United States
- Solar zone
- Zone 3 (good)
- Best month
- June (6.4)
- Worst month
- December (2.3)
- Climate
- Temperate · 15.3°C
Monthly solar breakdown
| Month | GHI | Clear-sky | DNI | DHI | Temp °C | Humid % |
|---|---|---|---|---|---|---|
| Jan | 2.65 | 3.51 | 4.21 | 0.96 | 3.4 | 80 |
| Feb | 3.32 | 4.57 | 4.28 | 1.25 | 5.2 | 79 |
| Mar | 4.35 | 5.91 | 4.61 | 1.65 | 9.5 | 78 |
| Apr | 5.55 | 7.13 | 5.23 | 2.04 | 15.2 | 75 |
| May | 6.07 | 7.76 | 4.96 | 2.46 | 20.0 | 75 |
| Jun | 6.41 | 7.87 | 4.88 | 2.67 | 24.7 | 72 |
| Jul | 6.20 | 7.56 | 4.60 | 2.66 | 26.7 | 70 |
| Aug | 5.52 | 6.90 | 4.29 | 2.37 | 25.8 | 73 |
| Sep | 4.65 | 5.99 | 4.37 | 1.87 | 22.2 | 75 |
| Oct | 3.71 | 4.83 | 4.81 | 1.22 | 16.0 | 77 |
| Nov | 2.90 | 3.71 | 4.59 | 0.95 | 9.7 | 77 |
| Dec | 2.31 | 3.13 | 3.79 | 0.89 | 5.7 | 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 2.31 kWh/m²/day, 0.77 system efficiency.
About solar in Raleigh
Raleigh, United States has a temperate climate with meaningful seasonal variation in solar resource. Its annual peak sun hours average 4.47 kWh/m²/day, a good solar resource by global standards.
The strongest month in Raleigh is June (summer) at 6.41 kWh/m²/day, and the weakest is December (winter) at 2.31 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.
Raleigh'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 Raleigh?
- Raleigh averages 4.47 peak sun hours per day annually, ranging from 2.31 in December to 6.41 in June.
- How many solar panels do I need in Raleigh?
- Panel count depends on your daily load. At Raleigh's annual average of 4.47 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 Raleigh?
- Sizing against Raleigh's worst month (December, 2.31 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 Raleigh's solar resource compare globally?
- Raleigh sits in solar zone 3 out of 5 (where 5 is strongest) at 4.47 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 much does winter reduce solar output in Raleigh?
- Raleigh's worst month (December) delivers 2.31 kWh/m²/day — about 36% of the summer peak of 6.41. Off-grid systems here typically oversize 1.5–2× or pair with a backup source.
- Do cloudy days significantly affect Raleigh's solar?
- Partly. Diffuse light still produces 10–25% of clear-sky output. Raleigh's 4.47 kWh/m²/day already reflects average cloudiness, so no further derating is needed for sizing.
- What panel tilt works best in Raleigh?
- At Raleigh's latitude (36°), a fixed tilt near 36° balances year-round yield. Winter-heavy loads favor latitude + 15°; summer-heavy, latitude − 15°.