We don't have many 105 degree days here, but we do have a few bad winter days, and I avoid riding in them. I think it's fine to avoid the bike on the worst weather days, whether they're hot or cold. Don't feel bad for using the right tool for the job.

The evidence is out. The pros of smoking are vastly outweighed by the cons of smoking. Smoking is bad. On the other hand, cycling is good. You might get killed on the road, but cyclists live longer and healthier than inactive people.