[cimmanom]

Tough to do/enjoy when there’s snow on the ground and a wind chill of 5F. Not all of us live in sunny California.

[beatgammit]

Gym membership? That's what I do, and I try to bike the ~1 mile to the gym regardless of weather.

Other than that, there are plenty of inside options for that, like yoga (plenty of yoga series on YouTube), body weight fitness (pushups and whatnot, no equipment needed, though rings and/or pull-up bar are very handy), or aerobics (I count Just Dance games in that category), depending on what you're in to.

[RugnirViking]

For what its worth I live in denmark and I really enjoy wrapping up warm and going out for walks in the snow.

And of course afterwards you can light a candle and relax with a hot chocolate or some tea in the warm.

Why choose to live in a place like this if you don't enjoy it?

[cimmanom]

Career opportunity. Proximity to family and friends.

[adrianmsmith]

You could buy an exercise bike?

Or do cardio exercises by watching various YouTube channels? (This is how my friend keeps fit.)