Why do we start the new year in January?!

Ritualistically, beginning our new year on Jan. 1 every 12 months is like creating a rule that every new marriage must be launched with an argument about thermostat settings. January, in all its dreary awfulness, has to happen, but it shouldn’t be allowed to set the tone for an entire year.

That’s why our calendar system should be changed so that each new year begins on April 2, which, not coincidentally, is the first day of the Major League Baseball season in 2017, and under our new “bright ’n’ cheerful” calendar, would be so forever.

This early January thing just isn’t working out, at least not in New York. By Tuesday, when most people returned to work and by tradition they would have attempted to get serious about making changes in their lives, it was all most Long Islanders could do to crawl out of bed and make coffee.

The weather was that horrible, rainy “just warm enough not to be snow because snow might make someone happy” that leads to Web-surfing real estate listings in Costa Rica. And work attendance seemed to fall into three categories:

• Way too sick with the flu bug or the lung crud to come in.
• Sick with the flu bug or lung crud but unwilling to waste a sick day at home, so look out, buddy, I’m coming in!
• Healthy, terrified and barricaded in conference room A, ready to fight off the sickies with a Swingline stapler and 128 ounces of Purell.

January is not the right time to try to start a new year. The beginning of a new year should be a time for people to take stock of their lives and plan the positive changes that will hurtle them forward into happiness. It’s a time to commit to that new exercise regimen or diet. It’s a time to rededicate ourselves to building better marriages or perhaps seeking really top-notch divorce decrees. It’s a time to become all-star professionals and stop making “if you walk around with a file in your hand people think you are busy” our career strategy.

But how are we supposed to turn over a new leaf in our lives when it’s so nasty out we can’t even bring ourselves to bag up the nasty wet leaves in the yard?

And it’s not just the weather, which is only going to get worse, and the constantly circulating viruses and bacteria. Sports are about to go full-on blah: Between the Super Bowl on Feb. 5 and start of baseball, we’ll have to survive on basketball and hockey, the bread-and-water diet of the sports world. The mailbox will fill with insurmountable holiday bills for things we’re not going to believe we bought come full winter. “We paid $99.99 for your mom’s membership to the Calendar of the Month Club? What does that even mean?”

There’s nothing set in stone about starting the year on Jan. 1. In fact, in Great Britain and the colonies, until 1752, the new year started on March 25, which is pretty close to perfect. The change to Jan. 1 came with the adoption of the Gregorian Calendar, which is a better system for crop planning but would work just as well no matter when you start the year.

It was Washington Post sports columnist Thomas Boswell who said, “Time begins on Opening Day,” and he was right, not just because every baseball fan is bursting with hope, but because life itself bursts with hope in April in this hemisphere.

It is when the flowers bloom and the windows are thrown open, when the beaches and woods beckon, and romance is in the air. It’s when the world turns over a new leaf, and could inspire us to do the same.

When a wet and chilly dusk arrives under thick clouds at 3:30 p.m., most of us just want to turn over a thick quilt and huddle beneath it.

Lane Filler is a member of Newsday’s editorial board.