Key takeaways


olar panels can work even on cloudy days and produce electricity without direct sunlight. Nevertheless, you will be able to unlock its full potential only with sufficient sunlight and at least four peak sun hours.

What are peak sun hours?

Infographic: Peak sun hours explanation
Peak sun hours explanation

Before going on with your solar purchase, you will have to determine the number of peak sun hours in your area – the hours when the intensity of solar radiation reaches 1,000 watts per square meter. During these hours of peak sun, the sunlight is the most intense, allowing the solar panels to deliver their maximum solar output. Peak solar hours depend on the time of day, year, and geography.

Why are hours of peak sun important for solar, and how do they affect the solar system’s output?

First, before installing solar panels, you must ensure your location receives enough sunlight, and peak solar hours are the leading indicator here. In the US, a region is considered suitable for solar panels if it gets at least four peak sun hours – with this number of hours of peak sunlight, a solar system will produce enough electricity to be cost-efficient.

Panasonic Hit solar panels: cutting-edge technology for efficient energy generation and sustainability.

In addition, you need to know the average number of solar hours in your area to calculate how many solar panels you have to install: divide your monthly electricity consumption by the peak sun hours your property receives. In this way, the hours of peak sun will help you calculate the size of the PV system that is perfect for your household.

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Peak solar hours by state: how many hours of peak sun does each state receive?

Now let’s find out how many solar hours different US states receive. Below, the states are ranked according to the average hours of intense sun they enjoy.

State Average Peak Sun Hours:
1 New Mexico 6.77
2 Arizona 6.57
3 Nevada 6.41
4 Wyoming 6.06
5 Hawaii 6.02
6 Kansas 5.79
7 Florida 5.67
8 Oklahoma 5.59
9 California 5.38
10 Utah 5.26
11 South Dakota 5.23
12 South Carolina 5.06
13 North Dakota 5.01
14 Kentucky 4.94
15 Montana 4.93
16 Texas 4.92
17 Idaho 4.92
18 Louisiana 4.92
19 Colorado 4.87

20 Nebraska 4.79
21 Georgia 4.74
22 Missouri 4.73
23 North Carolina 4.71
24 Arkansas 4.69
25 New Hampshire 4.61
26 Iowa 4.55
27 Minnesota 4.53
28 Maine 4.51
29 Maryland 4.47
30 Tennessee 4.45
31 Mississippi 4.44
32 Wisconsin 4.29
33 Alabama 4.23
34 Delaware 4.23
35 Rhode Island 4.23
36 Indiana 4.21
37 New Jersey 4.21
38 Ohio 4.15
39 Vermont 4.13
40 Virginia 4.13
41 Oregon 4.03
42 Michigan 4.0
43 Alaska 3.99
44 Pennsylvania 3.91
45 Connecticut 3.84
46 Massachusetts 3.84
47 New York 3.79
48 West Virginia 3.65
49 Washington 3.57
50 Illinois 3.14

*Data from TurbineGenerator

As you can see, New Mexico, Arizona, and Nevada have the most significant average number of hours of peak sun.

Generally, West Coast is the sunniest region with around 5-8 peak sun hours; Golf Coast is not far behind with 4.5-6 hours of peak sunlight. Southern East Coast and Northern East Coast enjoy 4-6 and 3-5 peak sunlight hours, respectively, while Rocky Mountain receives about 4-5 peak solar hours. Mid-West has less sunlight, with only 2.5-5 peak sun hours.

How to find out the number of peak sun hours solar panels will receive in my area?

If you want to know the most accurate data about peak sunlight hours in your location, there are several ways to do this. To begin with, you can try simply searching hours of peak sunlight by your zip code – this is the best way to find the amount of sun in densely populated regions. The second method to learn the number of hours of peak sun is to use the Global Solar Atlas - an online tool that gives you a summary of solar power potential in different parts of the world, including the number of peak sun hours. And finally, you can purchase a solar irradiance meter to measure solar hours accurately.

My site receives less than 4 hours of intense sun. Does this mean I shouldn’t install solar panels?

We’ve mentioned before that for the optimal work of a PV system, the hours when the sun is at its peak should be at least four. But what if your area receives fewer sun hours?

You may think harvesting solar energy is barred from you if you have fewer peak sunlight hours. However, this is not the case: even the areas with less than four peak sun hours, you can still take advantage of installing solar panels.

Solar hours aren’t the only thing determining how cost-efficient solar panels will be. Along with the number of peak sun hours, you have to consider the cost of electricity and the available solar incentives. Sometimes, going solar turns out to be highly advantageous despite the lack of direct sun hours. Let’s take, for example, New York, where there are much fewer sunlight peak hours than in most US states - the Big Apple only ranks 47th for average hours of the peak sun. But the electricity costs in the state are high, while its solar incentives are often considered the best in the country. This makes solar competitive with fossil fuels in New York, even though it can’t boast many hours of peak sunlight. The situation is mainly similar for Massachusetts, where the number of sun peak hours averages only 3.84. However, generous incentives and high electricity costs make going solar worth it despite fewer hours of sunshine.

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How to leverage peak sun hours to make the most of your solar system

So how can you make the best of your solar system during the sun peak hours? Check out the tips below to squeeze the most out of peak sunlight hours.

Pair your solar panels with a solar battery to produce more power during the hours of peak sun

Solar panels tend to overproduce during intense sun hours, so it makes sense to use intense sunlight to the fullest. Store the extra energy your solar panels generate when the sun is bright and use it later when solar hours are over. This way, you will be provided with power 24 hours a day.

Take advantage of solar net metering

Net metering is a billing mechanism allowing solar owners to sell any excess solar power they generate to the utility. When your solar panels produce extra power during peak sun hours, you will be able to feed it to the grid and get credits later to offset your utility bills.

How to find out your locations peak sun hours with Global Solar Atlas

Key takeaways

  • Peak sun hours are hours when the average sun irradiance level equals 1000W per square meter.
  • Calculating the number of sun peak hours will show how many hours a day your panels will receive maximum sunlight. In addition, knowing the average hours of peak sun will help determine the size of the PV system you need.
  • Areas with around four peak sun hours are considered most suitable for solar panels. However, if your site receives fewer peak solar hours, switching to solar can still be more cost-efficient than using expensive electricity from the grid.
  • The West Coast of the United States enjoys the most sun hours in the country, making it the best region for solar, while Mid-West receives only 2.5-5 peak solar hours on average.
  • Leverage net metering and solar battery storage to benefit from peak sunlight hours.


Key takeaways

Peak Sun Hours Essentials: For efficient solar panel performance, aim for at least four peak sun hours, indicating when solar radiation reaches 1,000 watts per square meter.

Determining Peak Sun Hours: Calculate your area's peak sun hours before considering solar. In the U.S., a region is suitable for solar if it receives a minimum of four peak sun hours, ensuring cost-effective electricity generation.

State-wise Peak Sun Hours: States like New Mexico, Arizona, and Nevada lead in peak sun hours, with 6.77, 6.57, and 6.41 hours, respectively. The West Coast typically enjoys 5-8 peak sun hours, while the Mid-West averages 2.5-5 hours.

Factors Influencing Solar Viability: Peak sun hours aren't the sole determinant of solar viability. Consider electricity costs, solar incentives, and regional use cases. Despite fewer peak hours, areas like New York and Massachusetts remain competitive due to incentives and electricity pricing.

Optimizing Solar Systems: Improve solar system efficiency during peak sun hours by integrating solar batteries for energy storage and utilizing net metering to sell excess power back to the grid.

Key Takeaways: Understanding peak sun hours is crucial for evaluating solar efficiency and system feasibility. Even regions with fewer than four peak sun hours can benefit from solar with careful consideration of incentives and electricity costs. The West Coast excels in sun hours, while optimizing solar systems requires storage and net metering strategies.

May 9, 2023
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