I am lucky. I live in Southern California near the beach. I have a pool at my home. My golf club has a fitness center. So the weather is good almost all of the time, I have great exercise equipment convenient to me.
Right now I am using an elliptical cross trainer for 30 minutes and then weight machines for 15 minutes, trying to vary the weights from legs one day to arms the next. I am just starting with the weight routine and am sure I will be adjusting it.
I understand that everyone is not so fortunate. Weather is bad, fitness clubs are expensive, money is tight, maybe you are travelling much of the time.
There is something you can try, star jumps or burpees. As always, check with your doctor before you start.