What's the difference between astronomical and meteorological winter?

Uncle Goose manufactures your toy blocks and gifts in Grand Michigan. Right now, there’s snow on the ground. It gets dark early. It’s cold, and we’re wearing our coats, hats, scarves, and mittens. So it’s winter, right?

Not so fast. Even if it looks and feels like winter, there’s a difference between meteorological winter and astronomical winter.

Right now, Michigan is in meteorological winter. We’ve been in meteorological winter since December 1.

But Grand Rapids won’t be in astronomical winter until Saturday, December 21, 2019 at 11:19 pm EST. We call that date and time the winter solstice. It marks the beginning of astronomical winter.

So what’s the difference between astronomical winter and meteorological winter?

Astronomical winter is based on the position of the Earth in relation to the sun. Since the Earth’s axis is tilted, when the northern half of the planet is tilted away from the sun, the northern hemisphere experiences astronomical winter. The date of the start of all the astronomical seasons - winter, spring, summer, and autumn — can fluctuate a day or two every year. It marks the shortest day of the year. Every day after winter solstice gets longer and longer, until summer solstice.

Meteorological winter starts on the same date every year. It begins on December 1 and runs until the end of February - either February 28 or 29, depending on whether it’s a leap year or not. Because the meteorological seasons start on the same dates every year, it can make it easier to compare temperature ranges by season from one year to another. Meteorological winter usually coincides with how many people think of winter.

When many of us think of winter, we think of it as a cold and dark time of the year. We even call cold and snow “winter conditions.” So even though it’s not yet the solstice, meteorological winter is the time of year where it looks and feels like winter to most people in northern climates.

If you like to celebrate the winter solstice, it’s likely that you’re joyful that daylight hours will start to get longer. Whether you follow meteorological or astronomical winter: a little more daylight every day is something to celebrate!

Start a discussion: when do you think it’s winter? Do you use astronomical winter or meteorological winter to determine when it’s winter?