Category Archives: Climate

Are the Madison lakes ice-covered?

The Wisconsin State Climatology Office, housed at the University of Wisconsin-Madison, monitors and reports on the ice coverage of Madison lakes.

The office keeps a database of the ice-over and ice-out dates for three Madison-area lakes: Mendota, Monona and Wingra. These records extend back to the winters of 1855-1856 for Mendota and Monona. The record of annual ice cover of Wingra is spotty, but consistent starting in the winter of 1982-83. Due to the long record based on visual observations, it is no surprise that the rules of opening and closing have been handed down by oral tradition. Continue reading

Category: Climate, History, Seasons

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What were the weather highlights of 2023?

As we begin a new year, let’s look back on the weather of 2023. The most recent, and odd, weather event of the year was the warm temperature on Christmas Day, with a high of 54 degrees in Madison. That was only the seventh time since 1869 that the maximum temperature exceeded 50 degrees on Christmas.

The state received less than one-third of its usual precipitation in November. The statewide average temperature for the meteorological autumn (September, October and November) was 2.5 degrees above normal, which made it the eighth-warmest autumn on record. In October, the 4.14 inches of statewide average precipitation was 1.13 inches above the 1991-2020 normal. This helped to alleviate our drought conditions. Continue reading

Category: Climate, History, Meteorology

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What happens on the winter solstice?

Astronomical winter begins at the winter solstice, which happened this year for the Northern Hemisphere at 9:27 p.m. Central Standard Time on Thursday, Dec. 21. Winter south of the equator begins in June.

The Northern Hemisphere winter solstice occurs at the time the sun is at its southernmost point in the sky. At this time, the sun is overhead at noon on the Tropic of Capricorn, approximately 23.4 degrees south of the equator. Continue reading

Category: Climate, Meteorology, Seasons

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Does fall give any hints about the intensity of the coming winter?

Each winter we keep track of the areal extent of air colder than 23 degrees Fahrenheit at the 850 mb pressure level (about 1 mile above sea-level) around the entire Northern Hemisphere. This measure allows us to characterize the intensity of the winter season with respect to the lower tropospheric temperature.

Over the past 75 seasons there has been a systematic decrease in the December-January-February, or DJF, average areal extent of about 4.6%, and this is an unequivocal sign of global warming, measured in the winter season. Continue reading

Category: Climate, Seasons

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What is the National Climate Assessment?

The U.S. National Climate Assessment is mandated by the Global Change Research Act of 1990. The assessment is conducted about every four years and is an authoritative scientific analysis of climate change risks, impacts and responses in the U.S.

The nation this month completed the Fifth National Climate Assessment, or NCA5. The National Oceanic and Atmospheric Administration is the administrative agency for NCA5 and certifies that the report meets Information Quality Act and Evidence Act standards. The assessment is an extensive process that includes internal and external review from federal agencies, the general public and external peer review by a panel of experts. Continue reading

Category: Climate, History, Seasons, Severe Weather

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