Growing daylight, and making ice on lakes

"As the days grow longer the cold grows stronger." - Weather proverb

That old weather proverb rings true as we get ready to welcome 2015 in Minnesota.

There's often sound meteorological science behind many weather proverbs. Astute intuitive observations by our weather-savvy ancestors reflected science that may have been unknown at the time. The power of observation can lead to questions that trigger us to ask why a certain pattern keeps repeating, which leads to evidence and eventual proof in the natural world.

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Ah, science.

Case in point? Longer days and deepening cold in winter.

"Seasonal lag" produces the coldest days on average nearly a month after the winter solstice in late December. It takes time for added daylight and small daily increases in solar isolation to have a warming effect. Just like when you turn on your stove, it takes time for the extra energy to heat up the soup.

The 23.5 degree tilt of earth's axis focuses more solar radiation on the southern hemisphere in December, and we get winter in the north.

EarthOrbit
NOAA

Growing daylight

You can already notice growing daylight in the evening hours as we move past the winter solstice.

  • 4:32 pm: earliest sunset of the year on December 15 at MSP Airport

  • 4:42 pm: sunset on New Year's Eve

  • +10 minutes: gain in extra daylight in the evening in the past two weeks

  • +1 minute per day: sunset now getting one minute later per day

Increases in evening daylight are starting to add up now. You notice brighter skies on your evening drive home now. In just a little over two weeks the sun sets at precisely 5 p.m. on January 17. Suddenly it's not dark just after lunchtime anymore. Evening becomes a daylight concept again soon.

We gain most of our additional daylight in the evening these days thanks to the elliptical nature and speed of earth's orbit around the sun.

Here's a closer look at daylight trends the next week for the Twin Cities from timeanddate.com.

1229 daylight
timeanddate.com

Brighter days and and increasing evening daylight — two reasons you're probably feeling a little more upbeat, even as colder days and the dead of winter descend on Minnesota.

Mild Citrus Bowl Forecast

The perks of getting into a New Year's Day Bowl for Minnesota football fans? How about a trip to somewhere much warmer?

citrus-650x342

The forecast looks pretty good right now for New Year's Day in Orlando.

1229 orlando
NOAA

Roller coaster winter temperatures

Closer to home we ride the winter temperature roller coaster the next two weeks. Periodic sub-zero air masses slide south, punctuated by milder days as temperatures moderate into the 20s. The more typical winter chill is not the sustained, deep polar vortex-driven cold of last winter.

1229 kky5
Weatherspark

Making ice

The descending cold, with nights below zero is helping make ice on Minnesota's lakes. Friends report just 7 inches of ice thickness in the past few days on Carson's Bay in Lake Minnetonka. It's not safe yet for many cars or trucks to be on the ice. It will take a week of sub-zero lows to build "safer" ice. Give it time this year, don't push your luck on thin ice.

More: Why thin ice is hard to detect

Stay warm and enjoy the increasing daylight.