Category Archives: Climate

Why is Memorial Day weather so fickle?

Memorial Day weekend weather can be absolutely glorious in Wisconsin or it can be rainy and cold.

Perhaps no other major holiday suffers from such a Jekyll-and-Hyde split in our expectations, and there are really good scientific reasons that underlie this duality. Continue reading

Category: Climate, Meteorology, Seasons

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Is the reduction in air traffic affecting the weather?

The COVID-19 pandemic has caused a reduction in air traffic. This reduction has had at least two impacts so far, one relating to the exhaust from aircraft engines and the other to weather forecasts.

Exhaust from aircraft engines can be seen sometimes as condensation trails, or contrails. The exhaust of an aircraft contains both gas and tiny particles called aerosols. Both of these are important in the formation of contrails. Contrails form when water vapor condenses and freezes around the small particles that exist in aircraft exhaust. Continue reading

Category: Climate, Phenomena

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Did spring come early this year?

Astronomically, spring occurs when the sun’s rays strike the equator at noon at an angle that is directly overhead.

This particular time varies from year to year due to variations in Earth’s orbit about the sun. In the Northern Hemisphere, the vernal, or spring, equinox (“equi” meaning “equal,” and “nox,” “night”) occurs sometime between March 19 and 23, but often on March 20 or 21. Continue reading

Category: Climate, Meteorology, Seasons

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How severe was our just-completed meteorological winter?

Employing data from the last 72 winter seasons — December, January and February — we have been examining the size of the area one mile above sea level over the Northern Hemisphere that was colder than 23 degrees.

After recording the warmest December ever, since the cold area was the smallest found using this methodology, this year’s winter season ended up as the fifth-warmest of the last 72 — fairly impressive. In fact, perhaps not surprisingly, 14 of the 20 warmest winters by this measure have occurred since 2001-02, with the warmest being 2014-15. Continue reading

Category: Climate, Seasons

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How did this winter compare to average?

Less than two weeks ago, on Feb. 17, Madison reached its annual climatological amount of snowfall — 51 inches — with a 5.2-inch fall. This is yet another wrinkle in what has been a very unusual winter.

Almost everyone remembers the early snowfalls of late October and early November that delivered a total of 16 inches of seasonal snowfall by Nov. 11. Perhaps forgotten, however, is the seven-week snow drought that followed, with the next 1-inch snowfall — 1.5 inches to be exact — finally arriving on Dec. 30. Continue reading

Category: Climate, Seasons

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