What’s the Difference Between Meteorological Winter and Astronomical Winter?

While we all have different things that signal the change of season for us — like how some people begin that fall starts as soon as Starbucks releases its pumpkin spice latte, while others believe that winter starts the second that the first snowflake falls — scientists have determined that there are some significant identifiers that signal the change of seasons, and they are pretty varied depending on who you ask.

That's because winter is separated into astronomical and meteorological seasons.

So what's the difference between the two? And how do you know which one you're in? Keep reading as we explain the difference between meteorological winter and astronomical winter so that you can understand when the season truly starts, and why it matters when it does.

When it comes to the difference between the two different types of winter, the difference lies mostly in the dates. That's because the Mount Washington Observatory blog says that meteorological winter starts first, and it begins at the start of each December. Astronomical winter starts later in the month, and doesn't truly begin until the December is almost over.

The reason for the two different dates has a lot to do with the average temperatures that are found during these days.

That's because overall temperatures tend to be lower in December through February, as opposed to January through March, making the meteorological winter a better way to talk about winter weather. However, this isn't always true, especially with climate change, and the Mount Washington Observatory blog notes that in 2024, March temperatures were actually colder than December's, which made the astronomical winter period a more accurate range for traditional winter weather.

Wondering whether you're in meteorological winter or astronomical winter? AccuWeather says figuring it out is as easy as looking at the date on the calendar. That's because astronomical winter starts on the winter solstice, which traditionally falls somewhere between Dec. 20 and Dec. 22. These dates will vary depending on a few different things, including whether it was a leap year and the elliptical shape Earth orbits around the sun.

This season tends to run between 89 and 93 days.

Meteorological winter is a bit easier to pinpoint the start of, since it begins each year on Dec. 1. This season lasts for 91 days each year, and AccuWeather says it follows a pretty easy-to-understand schedule since it lines up with the rest of our planet's seasons, which include:

• Spring in March, April, and May
• Summer in June, July, and August
• Fall in September, October, and November
• Winter in December, January, and February

So why the differences? It's more than just following the schedule that most accurately aligns with the weather outside. It really comes down to making it easier to track data about the season, according to AccuWeather, which says that this information is then used for making predictions about everything from agriculture to commerce.