Is it better to exercise outdoors?
Weather permitting, yes. Unless it is brutally hot, cold, pouring rain, or blizzard conditions, it is healthier to exercise outdoors.
Fresh air, sunshine, and the sounds and scenes of mother nature can't be replicated indoors. Before the wonderous technology age, physicians would encourage parents to send their children outside to play. Child or adult, you tend to exercise longer outside.
You also have to deal with the elements. Wind, unless at your back, adds resistance to your bike, run, or walk. The sun, along with supplying vitamin D, has a thermogenic effect on your metabolism. That loose dog, will speed up your pace, whether you like it or not! So, bring your dumbells out on the deck or lawn, get new jogging or walking shoes, put air in those bicycle tires, and get outside.
If you dress appropriately for the season, hydrate yourself, and slap on the sunscreen, you can workout outdoors year round. Fall is a great season to start, as the hot summer days fade to a memory. Take a deep breath of fresh air and get going.
What about the winter, you ask? When the time is right, I'll outline an outdoor winter workout. Ever try to walk fast through 12 inches of snow?