Maybe you can't go for a two-hour ride, but can you hike or go for a long walk instead? How about one hour outside and one hour inside? Have you considered renting equipment and trying a new sport like Nordic skiing or snowshoeing? Look for ways to exercise outside.
Recruit the Help of Friends and Family
If it's cold and the wind is blowing straight out of a single direction, maybe you could ride with a tailwind and have someone pick you up? If the cold conditions create some risk, perhaps you can arrange a sag vehicle in exchange for lunch? Perhaps you could combine your endurance adventure with a visit to an old friend?
In any case, let someone know where you're going and how long you expect to be gone in the cold conditions. At minimum, leave a note on your counter telling what time you left, where you planned to go and what time you expect to be back. Carry your cell phone.
Consider That You Are Able
Certainly you know at least one person that is not able to exercise for whatever reason. Perhaps the person you know has an illness or an injury. You have the health and ability to get outside and move. Never take this privilege for granted. Get out the door and be grateful for your health.
Ask Yourself How You Will Feel Tomorrow
If you decide not to exercise outside today and instead choose to do nothing, how will you feel tomorrow? Will you feel good about yourself? If you do head outside in cold weather, will you feel proud that you did something rather than nothing, even if the workout was shortened? Always take actions that make you feel good.
Seek Inspiration in Others
There are inspiring people everywhere, if you take the time to notice. It might be the lone soul on the road going for a run while you're in your car, or the person that commutes by bicycle in a snowy state. I can guarantee that no matter the outdoor temperature, someone is out there having fun and taking one more step towards successfully reaching a personal goal. That someone might be inspiring others.
You can be that person.
Set your goal: Find a triathlon.