Author Archives: WeatherGuys Editor

What causes a double rainbow?

The classic rainbow is a single, bright, colored arc. Red is the outermost color of this arc, and violet is always the innermost color.

On occasion, you may have seen two rainbows at once. The lower rainbow is the primary rainbow and the higher, fainter, colored arc is the secondary rainbow. The color sequence of the secondary rainbow is opposite to the primary; red is on the inside of the arc and violet on the outside. Continue reading

Category: Meteorology, Phenomena

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How do you measure how hot the summer is?

One reasonable way to gauge how hot a summer season was is to consider how many days that year reached 90F or above. It turns out that this number is extremely variable here in Madison.

From 1971 to 2016, the average number of days at or above 90F in Madison is 10.9. As is often the case with statistics, however, the average does not convey a sense of the variability. A better way to express that variability is by calculating the standard deviation, which, when added to or subtracted from the average, sets a range in which approximately 2/3 of the years will fall. Continue reading

Category: Climate, Meteorology, Seasons

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When is the summer solstice?

The summer solstice in the Northern Hemisphere is the day when the sun is farthest north. In 2017, this occurs Tuesday at 11:24 p.m. Central Time. As Earth orbits the Sun, its axis of rotation is tilted at an angle … Continue reading

Category: Seasons

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What is a derecho?

A derecho (pronounced deh-RAY-cho, a Spanish word meaning “straight ahead”) is an hours-long windstorm associated with a line of severe thunderstorms.

It is a result of straight-line winds, not the rotary winds of a tornado — hence its name. Derechos in the United States are most common in the late spring and summer (May through August). Continue reading

Category: Meteorology, Phenomena, Severe Weather

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Why withdraw from the Paris Climate Accord?

President Trump’s decision to withdraw the U.S. from the Paris Climate Accord last Thursday is a disheartening blow to the longstanding idea that sound science should play a role in the formation of public policy in our country.

This notion, in fact, was central to the creation of the National Academy of Sciences by the first Republican president, Abraham Lincoln in 1863. Lincoln and the Congress charged the Academy with providing independent, objective advice to the nation on matters related to science and technology. Continue reading

Category: Climate, Uncategorized

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