Effects of Weather on Solar Panels

When you invest in a solar energy system, you naturally will worry about the effects of weather on those essential solar panels. Situated out in the open, faces tilted to the sky, they are exposed to all weather conditions, not just the benefits of sunlight. Despite their fragile appearance, solar panels can withstand fairly extreme weather conditions and emerge unscathed.

Reduced Absorption

Engineers have designed solar panels to withstand weather extremes.

The most common effect of inclement weather on solar panels is to temporarily reduce their capacity to absorb solar energy. Clouds covering the sun can cut Photovoltaic (PV) array---solar panel---energy absorption by 50 percent and more, depending on how much daylight they diffuse. However, as long as there is light in the sky, your panels should be to collect some solar energy, even though the sun is not directly shining on their surfaces.

In desert areas, dust storms can reduce energy absorption in your PV array. Similar to cloud cover, a thick layer of blowing dust will obscure daylight and lessen the amount available to your solar panels. The first solar power plant in Abu Dhabi experienced a reduction in energy output of as much as 40 percent during a week of dusty weather (see Reference 2).

In winter, snowfall covering the surfaces of your PV array blocks solar energy absorption. Usually, however, the snow will slide off due to the tilt of the panel or melt away quickly as the panel warms to daylight. If not, you will have to manually remove the snow before your solar system will return to energy production.

Surface Damage

A snow coating on your PV array can block sunlight.

Weather conditions such as thunderstorms and hailstorms have the potential to damage the surfaces of your solar panels. Despite the fact that panel manufacturers design their products to withstand the perils of severe weather, including lightning, high velocity wind, and extremes of heat and cold, your PV array can be damaged.

UL---Underwriters Laboratories---Listed and UL Tested panels undergo hail testing, but will pass as long as the panel does not shatter. There is still the possibility that a severe hail storm will crack the surface glazing of your PV array. If lightning hits your solar panels, even if you have supplemented the installation with a grounding system to defuse the impact, it is likely to damage the array.

Even though your panels are securely installed according to the manufacturer's specifications and are rated to withstand winds of up to 80 miles per hour, you may get stronger gusts, which could damage the panels or knock them out of alignment, necessitating replacement or repair.

Power Boost

Good conditions for the edge of cloud effect.

A positive effect of inclement weather on solar production is a phenomenon known as "the edge of cloud effect." In certain conditions, the presence of cloud cover actually augments the amount of energy, which your panels can absorb. When groups of cumulus clouds---white, puffy fair-weather clouds---drift through the sun's rays, they reflect the sun and increase its power, in the same way that a magnifying glass intensifies light. The edge of cloud effect usually provides only a fleeting boost to sunlight which may or may not make up for lowered absorption when the clouds cover the sun.