The weather is getting cooler and the days are getting shorter.

As seasonal changes begin, it’s easy for people to get into a rut when it comes to dieting and exercise.

And that rut can translate into extra pounds once the holiday parties start rolling around.

But there are ways to avoid winter weight gain. Marc Santa Maria, regional director for group fitness at the Crunch fitness center in New York City, offered these five suggestions:

1. Work out with a partner. It’s easy to blow off your morning run if you’re the only one doing it. But, if you have a friend, waiting in the park for you, it’s a little different, said Santa Maria.

“Have a workout buddy and stick with it,” he said. “Take turns being in charge of the day’s workout because some days you just don’t want to be the one in charge.”

2. Exercise in small increments. If an hour workout seems daunting, try exercising in smaller chunks, suggested Santa Maria.

“Even if you split it up, say you do 15 minutes on an elliptical and 15 minutes on a treadmill, then, later on, maybe you can pop in for the first half of an exercise class,” he said. “Most teachers don’t mind if you skip out early.”

3. Move outdoor activities indoors. Many fitness centers now offer outdoor activities inside.

“At Crunch, we have an indoor snowboarding class,” Santa Maria said. “So even if you don’t yet have the option of snowboarding because there’s no snow out there. You can take a boarding class, which is something that can be totally motivational and fun until the snow is out there.”

4. Work toward an event. It might be cold out, but if you’re planning a winter vacation to a tropical paradise, you can use that as motivation to stay fit in the meantime.

“We had a surfboarding class in the summer and it was good because we worked toward taking an actual surfing vacation,” he said. “But even if you’re not going somewhere warm, you can use something like a snowboarding trip as a reason to gear up and get in shape.”

5. Indulge at holiday parties. It’s true, you can eat at holiday parties as long as you enjoy it, said Santa Maria, suggesting that partygoers sample a little (little being the key word) of everything.

“If you take a little bit of everything and still need seconds, then have seconds of the one thing you really loved and enjoy it,” he said. “When you try to limit things, it almost works against you. So instead of saying, ‘I can’t have macaroni and cheese,’ try a little bit of it and really enjoy it. People get caught up at parties and they just start inhaling things. But if you enjoy it, it really makes a difference.”