When people first start thinking about going solar, one of the most common questions is: "Will solar panels even work where I live?" The answer depends on a few things, but one of the biggest factors is how many solar hours your location gets each day.
In this post, I’ll break down what solar hours are, how you can figure them out for your area, and why they’re so important if you want to build a reliable and cost-effective solar setup.
What Are Solar Hours?
Solar hours (or peak sun hours) refer to the number of hours per day when the sunlight is strong enough to be considered ideal for solar production. That means direct sunlight at 1,000 watts per square meter — basically, the perfect intensity for your panels to operate at their rated capacity.
Now, this doesn’t mean total daylight hours. You might have 12 hours of daylight, but only 4–6 of those count as peak sun hours depending on the weather, season, and your location on the planet.
Why Solar Hours Matter
Knowing your average daily solar hours is super useful because it helps you:
- Estimate how much electricity your system can produce
- Decide how many solar panels you actually need
- Understand your return on investment
- Avoid over- or under-sizing your system
For example, someone living in Southern Spain will likely have more solar hours than someone in Germany — and their solar setup will work differently even if they install the same number of panels.
How to Calculate Solar Hours
There are a few ways to do this, and I've tested most of them while building our app. Here's what works best:
1. Use a Solar Calculator Tool
You can use our built-in tool in the Sunort app (or other tools like Meteostat, PVGIS, or Global Solar Atlas). Most of these work like this:
- You enter your location, either by typing your city or using GPS
- The tool gives you average daily solar radiation data
- You convert that into peak sun hours (or the tool does it for you)
Example: If your location gets 150 kWh/m² per month, divide that by 30 days and then by 1,000:150 ÷ 30 = 5 kWh/day → 5 peak sun hours per day
2. Look Up Public Solar Maps
Some governments or utility companies publish solar potential maps that show how much sun different regions get per year. It’s not always super detailed, but it can give you a good starting point.
3. Check Historical Data
If you’re comfortable with data, you can dig into monthly average solar irradiation numbers (kWh/m²), which are often published by meteorological services. Once you have that, the conversion to sun hours is the same — divide by 30, then divide by 1,000.
What Affects Your Solar Hours?
Even if you live in a sunny place, a few factors can mess with your daily sun hours:
- Latitude: The closer you are to the equator, the more consistent your sun exposure year-round.
- Season: Winter months usually have fewer peak sun hours.
- Cloud Cover & Weather: Obvious one — cloudy and rainy days reduce sun intensity.
- Shading: Nearby trees, buildings, or mountains can reduce hours, even in sunny regions.
- Orientation: Panels facing true south (in the Northern Hemisphere) or true north (in the Southern Hemisphere) will usually perform best.
How Our App Helps You
When I was developing Solarix, I wanted it to be something I’d use myself — so calculating solar hours was one of the first features we built.
Inside the app, you can:
- Share your location or search any city
- Get average solar hours by month
- Compare different seasons
- Factor in solar hours when planning panel size or estimating potential savings
This way, you’re not guessing — you’re planning with real data.