Brighter spring days: Minnesota gaining 3 minutes of daylight per day now

As the song says, here comes the sun.

Minnesota is now gaining daylight faster than any time of year as we approach the spring (Vernal) equinox Sunday.

The Twin Cities is gaining 3 minutes and 9 seconds of daylight per day this week. That’s the fastest daylight gain of the year. I’ve highlighted the daily daylight gain in the Twin Cities in the image below.

Our sunset time in the Twin Cities is 7:20 p.m. Wednesday. The sun will set at 7 p.m. or later in the Twin Cities through Sept. 27. Sunset time in the Twin Cities peaks at 9:04 p.m. in late June.

Higher sun angle

One very important aspect of our bright spring days is the higher sun angle. The sun reaches 45 degrees above the horizon on the spring equinox Sunday. This higher sun angle and intensity are equal to September 20.

The higher sun angle and intensity help melt snow cover more quickly now. That’s a big part of our warmup process in spring. Shorter nights also mean air masses don’t have as much time to cool. That means higher over-light minimum temperatures, which sets a higher “floor” for the next day’s potential temperature rise.

Here’s more on earth’s astronomical seasons from NOAA.

We all know that the Earth makes a complete revolution around the sun once every 365 days, following an orbit that is elliptical in shape. This means that the distance between the Earth and Sun, which is 93 million miles on average, varies throughout the year. During the first week in January, the Earth is about 1.6 million miles closer to the sun. This is referred to as the perihelion. The aphelion, or the point at which the Earth is about 1.6 million miles farther away from the sun, occurs during the first week in July. This fact may sound counter to what we know about seasons in the Northern Hemisphere, but actually the difference is not significant in terms of climate and is NOT the reason why we have seasons. Seasons are caused by the fact that the Earth is tilted on its axis by 23.5°. The tilt's orientation with respect to space does not change during the year; thus, the Northern Hemisphere is tilted toward the sun in June and away from the sun in December, as illustrated in the graphic below.

Lag of seasons

Just like it takes time for water to heat on your stove after you turn the burner higher, it takes time for the atmosphere to heat up as our sun intensity increases. The lag of seasons is almost a month most times of the year.

Here’s more from NOAA.

There is a lag between the longest day of the year and the warmest average temperatures for most mid and high-latitude locations.

The maximum daily temperature occurs nearly 3 weeks later than the summer solstice in mid-July. Just as the warmest part of the day usually occurs several hours after noon, when the sun is highest in the sky, so too does the warmest part of the summer lags the summer solstice. This lag is due to the time required for ground and water to heat up. Average temperatures continue to climb until the sun drops lower in the sky. While the effect is evident in a daily temperature plot, it is more readily apparent by looking at changes in the monthly average temperature.

So as you see our sunlight increasing and feel the extra warmth, think about the effect it’s having on our atmosphere this time of year.

The change is coming, Minnesota.