My commute is under 10KM, so riding always seems like more effort than it's worth to me by the time I gear up and then have to stow all my gear at work, etc. I also hate wearing long pants in the summer so I also have the dilemma of riding to work in long pants only to change into shorts, and then back again. I've been known to cheat a few times over the years and ride in shorts to work, but I always feel all sorts of wrong doing that.
In the end, it's more work vs enjoyment at that point.
If I had a longer commute, hands down I'd do it on the bike. I have a radio and a cup holder for my coffee, so temperatures aside (you take what you get on a bike, isn't that why we all ride?) I'd find it way more enjoyable vs the cage.