Solar Peak Sun Hours in Nigeria
Peak sun hours vary by up to 37% across Nigeria. Here’s the regional, city and state data, and the design PSH figures that should actually go into your sizing calculation.
If you’ve ever compared two solar quotes and wondered why the panel counts don’t match, the answer is often where you live, not the installer. A system in Kano can produce up to 37% more energy per day than the identical system in Lagos, purely because of how much sun each city actually gets (Chanchangi et al., 2023, Environment, Development and Sustainability). Get that regional number wrong, and every panel count, battery bank, and quote built on top of it is wrong too.
This post covers what peak sun hours (PSH) actually means, the regional and state-level data behind it (including where the widely-shared state table falls short), and the design PSH figures, weighted to your worst month rather than the annual average, that should actually go into your sizing calculation. For what your system really produces once losses are accounted for, see the companion post, What Your Solar Panels Will Really Produce in Nigeria.
What Are Solar Peak Sun Hours?
Nigeria’s abundant sunlight makes it one of Africa’s strongest solar markets. But “abundant” isn’t a design number. Understanding peak sun hours (PSH) is what turns that general fact into a system that actually meets your load, whether you’re sizing a home backup setup, a commercial rooftop, or an off-grid mini-grid.
Peak sun hours (PSH) is the number of hours per day the sun would need to shine at full test intensity, 1,000 watts per square metre, to deliver the energy your location actually receives across the whole day. It isn’t daylight hours.
Example: Lagos gets roughly twelve hours of daylight year-round, but only about four peak sun hours. The early morning and late afternoon sun contributes, but weakly. PSH compresses the whole day’s energy into an equivalent number of full-strength hours.
At 4.5 PSH, each 1 kWp of panels produces about 4.5 kWh a day, before losses.
Why Peak Sun Hours Matter
Your local PSH figure is the starting input for almost every solar decision:
- Estimating output: how many kWh a given array will realistically produce per day
- Sizing your system: more PSH means fewer panels needed for the same load; less PSH means more
- Planning storage and backup: low-PSH months are exactly when you need battery capacity or a supplementary source most
Get this number wrong, and every downstream decision (panel count, battery bank, inverter rating) is wrong with it.
Average Peak Sun Hours by Region
At the broadest level, Nigeria splits into five compass regions:
| Region | Approx. Peak Sun Hours/Day |
|---|---|
| Northern Nigeria | 6.0-7.0 |
| Southern Nigeria | 4.0-5.0 |
| Central Nigeria | 5.0-6.0 |
| Eastern Nigeria | 5.0-6.0 |
| Western Nigeria | 4.0-6.0 |
The pattern is consistent. The north’s dry, largely cloud-free climate gives it the highest solar potential, while the south and coast lose ground to rainfall and cloud cover. This is a useful first read. The state and city data below sharpens it considerably.
Nigeria’s Solar Resource: Measured City Data
National mean daily radiation runs about 5.25 kWh/m²/day, ranging from roughly 3.5 in the coastal south to 7.0 in the far north, a range independently confirmed in Chanchangi et al.’s 2023 Nigeria energy review (Environment, Development and Sustainability), which cites the same 3.5-7.0 kWh/m²/day spread from separate solar-resource studies.
Measured city figures from regional studies:
| City | Mean daily global solar radiation (kWh/m²) |
|---|---|
| Kano | 6.08 |
| Sokoto | 5.86 |
| Maiduguri | 5.71 |
| Jos | 4.84 |
| Abuja | 4.81 |
| Ado-Ekiti | 4.67 |
| Abakaliki | 4.69 |
| Asaba | 4.44 |
| Onitsha | 4.43 |
| Lagos | 4.42 |
The spread between Kano and Lagos is roughly 37%. Two identical arrays in those cities produce meaningfully different amounts of energy, which is why national rules of thumb mislead.
State-by-State Solar Radiation (Wider Comparison)
A wider industry roundup, the same table circulating across several Nigerian solar sites, puts numbers on more states than our own city dataset covers, sourced from the Global Solar Atlas (2021). Useful for spotting the state-level pattern; use the design PSH bands further down for actual sizing.
| State | Daily Peak Sunlight Hours | Annual Avg. Solar Radiation (kWh/m²) | Clear Sky Days/Year |
|---|---|---|---|
| Yobe | 7.2 | 6.25 | 270 |
| Kaduna | 6.8 | 5.75 | 250 |
| Kano | 6.6 | 5.50 | 240 |
| Katsina | 6.2 | 5.00 | 220 |
| Bauchi | 6.2 | 5.00 | 220 |
| Adamawa | 6.4 | 5.25 | 230 |
| Kebbi | 6.0 | 4.75 | 210 |
| Ebonyi | 6.0 | 4.75 | 200 |
| Enugu | 6.0 | 4.75 | 200 |
| Benue | 6.0 | 4.75 | 200 |
| Kogi | 5.8 | 4.50 | 200 |
| Niger | 5.8 | 4.50 | 200 |
| Borno | 5.8 | 4.50 | 200 |
| Akwa Ibom | 5.8 | 4.75 | 200 |
| Imo | 5.6 | 4.50 | 190 |
| Kwara | 5.6 | 4.50 | 190 |
| Jigawa | 5.6 | 4.25 | 190 |
| Anambra | 5.6 | 4.50 | 190 |
| Edo | 5.6 | 4.50 | 190 |
| Ogun | 5.6 | 4.50 | 190 |
| Cross River | 5.6 | 4.50 | 190 |
| Lagos | 5.4 | 4.25 | 180 |
| Delta | 5.4 | 4.25 | 180 |
| Ekiti | 5.4 | 4.25 | 180 |
| Ondo | 5.4 | 4.25 | 180 |
| Gombe | 5.4 | 4.00 | 180 |
| Bayelsa | 5.4 | 4.25 | 180 |
Design PSH by Region: Use These
These are design figures, weighted toward the worst months rather than the annual mean. This is the number that should actually go into a sizing calculation.
| Region | Annual average PSH | Design PSH | Worst season |
|---|---|---|---|
| Lagos, Port Harcourt, Calabar, Warri (coastal south) | 4.0-4.4 | 3.2-3.6 | June-August rains |
| Ibadan, Abeokuta, Benin, Onitsha, Enugu (inland south) | 4.4-4.8 | 3.6-4.0 | June-September rains |
| Abuja, Lokoja, Jos, Ilorin, Makurdi (middle belt) | 4.8-5.2 | 4.0-4.4 | July-August rains |
| Kaduna, Bauchi, Gombe, Yola (northern guinea) | 5.4-5.8 | 4.6-5.0 | Dec-Feb harmattan |
| Kano, Sokoto, Katsina, Maiduguri (far north) | 5.8-6.4 | 5.0-5.4 | Dec-Feb harmattan |
Quick Lookup: Which Band Is Your State?
- Coastal south: Lagos, Rivers, Cross River, Delta, Bayelsa, Akwa Ibom
- Inland south: Oyo, Ogun, Ondo, Osun, Ekiti, Edo, Anambra, Enugu, Imo, Abia, Ebonyi
- Middle belt: FCT (Abuja), Kogi, Kwara, Benue, Plateau, Nasarawa, Niger
- Northern guinea: Kaduna, Bauchi, Gombe, Adamawa, Taraba, Zamfara, Kebbi
- Far north: Kano, Sokoto, Katsina, Borno, Jigawa, Yobe
The extreme case is the far northeast. Yobe and parts of Borno sit at the very top of Nigeria’s solar resource, with markedly more cloud-free days per year than the coast (very roughly 250-270 clear-sky days a year against 180-200 in Lagos or Port Harcourt). It’s also where dust and harmattan losses bite hardest, so the design margin above still applies in full.
Factors That Affect Your Peak Sun Hours
- Geographic location: the north’s arid climate and minimal cloud cover give it the highest PSH; the south and coast lose ground to rainfall and cloud cover, as the tables above show directly.
- Seasonal changes: Nigeria’s rainy season (roughly April to October) cuts solar output, especially in the south. Harmattan dust does the equivalent job in the north between December and February. See below.
- Roof orientation and tilt: a south-facing roof at 15 to 40 degrees captures meaningfully more of the day’s sunlight than a flat or poorly oriented one.
- Shading: trees, neighbouring buildings, and rooftop obstructions cut your effective PSH below what the region alone would suggest. Site selection and panel placement matter as much as geography.
Why the Annual Average Is a Trap
A system sized on the annual mean works beautifully for eight months and fails for four. That’s a failed system, not a seasonal inconvenience, particularly because the bad months are usually the months when grid supply is also worst.
In the south, the enemy is rain. Lagos averages around 3.8-4.2 PSH annually, but July drops to roughly 2.8-3.2 while December through February can reach 5.0-5.5. Design on 4.0 and your system underperforms by about 25% for the three months you most need it. This is the single most common technical mistake in Nigerian residential solar.
In the north, the enemy is dust. Harmattan does two things at once: it thins the direct beam and coats the glass. Kano peaks near 7.0 kWh/m²/day from April to August, but December through February sees a 25-30% reduction from dust and lower sun angles. Northern systems need both a design margin and a real cleaning routine.
Either way, the practical rule: size for your worst month, not your average one.
A Quick Way to Estimate Output (and Why It’s Not the Whole Story)
For a rough first pass, multiply your region’s PSH by your system’s rated size:
Energy Output (kWh/day) = Peak Sun Hours x Solar System Size (kW)
Example: In Kaduna, at 6.8 PSH, a 5 kW system gives 6.8 x 5 = 34 kWh/day on paper.
That number is the nameplate estimate, not what lands in your battery. It skips inverter conversion, cable losses, panel heat, dust, and battery round-trip, together typically a 20-30% haircut on a Nigerian roof. Use the formula above to get in the right ballpark for system size, then read What Your Solar Panels Will Really Produce in Nigeria before you commit to a battery bank or a load budget.
Worked Example: Lagos vs. Kano
| Parameter | Lagos | Kano |
|---|---|---|
| Annual average daily PSH | 4.42 | 6.08 |
| System size | 5 kWp | 5 kWp |
| Daily DC energy (kWh) | 5 x 4.42 = 22.1 | 5 x 6.08 = 30.4 |
| AC energy at PR 0.82 (kWh/day) | 18.1 | 24.9 |
| Annual AC energy (kWh) | ~6,610 | ~9,100 |
| Annual savings at ₦209.50/kWh | ~₦1,385,700 | ~₦1,906,200 |
The 37% higher PSH in Kano produces 37% more annual energy and 37% more savings from the same installed capacity. These are annual-average figures for illustration: use the design PSH bands above, not the annual average, when actually sizing a system.
