Category Archives: Seasons

When does fall begin?

Even the least observant person has probably recognized by now that the days are growing shorter.

In fact, on Friday at 3:02 p.m., we will reach the autumnal equinox and the night will be as long as the day for the first time since late March. Continue reading

Category: Meteorology, Seasons

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What does the State of the Climate Report tell us?

The National Oceanic and Atmospheric Administration (NOAA) released its 27th annual State of the Climate report Thursday, and it was full of attention-grabbing news.

Topping the list was the fact that analysis of global temperature measurements revealed that 2016 bumped 2015 as the warmest year in 137 years of record keeping. In fact, 2016 was the third consecutive year of record warmth. Continue reading

Category: Climate, Meteorology, Seasons

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Was July a record wet month?

It seems likely that most of us would consider this month of July to be an exceptionally wet one and, in many ways, that is true.

First of all, we have received measurable rain on 11 days this month and a trace of rain on six other days. Thus, well over half of the days this month have involved precipitation. Continue reading

Category: Meteorology, Seasons

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Why does the sun melt ice on sidewalks even when the temperature is below freezing?

All objects exchange energy with their environment. They do this via conduction, advection, convection and radiation. If water is involved, a change in the water phase (liquid, solid or gas) also will involve an exchange of energy.

Conduction moves energy by physical contact. Convection results from hot air rising. Advection by the wind moves heat horizontally. Continue reading

Category: Meteorology, Seasons

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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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