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Spring comes bounding into view

A pooch ran free in North Point Park in Cambridge on a day of gorgeous, spring-like weather.
A pooch ran free in North Point Park in Cambridge on a day of gorgeous, spring-like weather.Lane Turner/Globe Staff

Although meteorological spring arrived nearly three weeks ago, astronomical spring — and the “first day of spring” most of us usually think of — arrives Saturday at 5:37 a.m.

Because of the mathematical equations we use to determine time, the length of day and night is not exactly equal on the first day of spring, but it’s pretty close. Of course we’ve been gaining daylight at a rapid pace over the past several weeks.

The rate at which we will continue to gain light from now until mid-June will actually slow down and then ultimately will gain just a few seconds in those final days before the first day of summer.

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During the equinoxes, both hemispheres receive equal amounts of daylight. (Image not to scale.)
During the equinoxes, both hemispheres receive equal amounts of daylight. (Image not to scale.)NASA/GSFC/Genna Duberstein

Since many of us are working from home you might have noticed the way the light is coming differently through windows compared to its angle just a month or two ago. This is because the position of the sun in our sky has been moving farther north since just before the winter solstice. Actually the past few days the sun was rising due east and setting due west.

If you’re not sure the exact orientation of where you live the next couple of days will give you an opportunity to know exactly what direction you are facing.

Earlier this week the length of time between sunrise and sunset overtook the time between sunset and sunrise, as we begin to approach our longest days. If you add in civil twilight, the roughly 30 minutes before sunrise and after sunset when it’s light enough to see outside, we have about 13 hours of light this time of year. I love including civil twilight when talking about daylight because it give us a full hour more of light than the gap between official sunrise and sunset.

All of this light magic is amazing and of course, the exact opposite thing is going to happen in the Southern Hemisphere, where the days will continue to shorten, the nights will outpace the daylight, and temperatures will be on the decline.

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The chart below shows our average increase in temperature until we get to the end of May. You can see how steep the incline is as the next few months bring about some of the most rapid temperature increases of the entire year.

Temperatures show a rapid increase during the next few months across greater Boston.
Temperatures show a rapid increase during the next few months across greater Boston.NOAA

The intensity of the sunlight should not be underestimated as we go through the next several weeks. By the time we get to early April the strength of the sun is similar to Labor Day and you can easily get burned in under an hour. Although the air temperature will not be as warm as it will be in late summer, the intensity of the sun isn’t any different.

Temperatures are forecast to be quite mild for this time of the year during the first full week of spring and although I expect some chilly weather between now and summer, I think it’s unlikely we’re going to have any more cold or snow.

Temperatures forecast for Logan Airport for the next two weeks.
Temperatures forecast for Logan Airport for the next two weeks.WeatherBell

Perhaps the vernal equinox on Saturday will give you time to reflect upon everything that’s happened since the last one.

I hope that one positive thing that’s come out of this pandemic dystopia is an appreciation for the seasons and a closer observation of the amazing changes in daylight that was occurring for millennia and so many of us have just been too busy to notice.

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