Category Archives: Seasons

Is our December abnormally warm?

The mildness of the first half of December in southern Wisconsin has probably not escaped anyone’s attention.

Despite the first visit of relatively cold air we just experienced over the weekend, both Madison and Milwaukee have already recorded the second warmest first halves of December in their respective records. Through Dec. 16, Madison’s average temperature for the month was 39.7 degrees, a full 14.4 degrees above the average. Continue reading →

Category: Meteorology, Seasons

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When is the winter solstice?

The winter solstice (In Latin, sol, “Sun,” and stice, “come to a stop”) is the day of the year with the fewest hours of daylight. In 2015, this occurs for the Northern Hemisphere on Dec. 21 at 10:48 p.m. CST.

As Earth orbits the sun, its axis of rotation is tilted at an angle of 23.5 degrees from its orbital plane. Because Earth’s axis of spin always points in the same direction — toward the North Star — the orientation of Earth’s axis to the Sun is always changing as Earth orbits around the Sun. Continue reading →

Category: Meteorology, Seasons

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What does it take for Lake Mendota to freeze?

As we head into December many people begin to watch the local lakes for the first signs of ice cover.

One of the most studied lakes in the world is our very own Lake Mendota. Among the various long-term observations of it that have been accumulated in the last 150-plus years are the ice-on and ice-off dates for each winter season. Continue reading →

Category: Meteorology, Seasons

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Can it be too cold to snow?

No, it is never too cold to snow.

It snows in Antarctica — where temperatures are minus 70 degrees — though only a few tenths of an inch.

To get snow, the always-present water vapor in the atmosphere has to be converted to ice crystals. How much water vapor is in the atmosphere depends on the air temperature. Continue reading →

Category: Meteorology, Seasons

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How do we measure an official snowfall for Madison?

Accurate and precise measurement of snow accumulation is a difficult task.

The measurement tools are simple: a ruler or yardstick that measures in inches and tenths of an inch. Continue reading →

Category: Meteorology, Seasons

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