How this week’s solar eclipse will alter the weather | CNN

Wednesday’s total solar eclipse will alter weather conditions along its path from the Arctic to western Europe. Changes to temperature, wind speed and humidity occur as the moon crosses in front of the sun during a solar eclipse and casts a shadow on Earth’s surface. This reduces the amount of solar radiation — sunlight and energy – that makes it to the surface. The more solar radiation blocked, no matter how brief, the more dramatic the weather changes. The effect is comparable to how shaded areas end up much cooler on a hot day than any place in direct sunlight. Wednesday’s eclipse will completely block out the sun along a narrow path in northern Russia, parts of Greenland, Iceland, Portugal and Spain, providing the opportunity for more noticeable changes in spots. Not all eclipse weather changes are created equal, though. The exact drop in temperature can vary widely based on other factors like cloud cover and the time of year. The biggest temperature drops usually happen during sunny summer afternoons when the sun angle is high in the sky. A higher sun angle produces more intense sunshine and elevated temperatures, so thermometers are more prone to cratering with a lo