This great post highlights the issue that I have with using a turbo, an exercise bike, a treadmill - or anything like that. When you're on it and thinking about the life you've led, I'm sure you never think "Aah, I remember the day I was on the turbo. It was great". You might, however think "Aah, remember the day I went for a cycle in the lashing rain. It was cold, but great".
This things are great for warm-up or recouperation, but as a replacement for getting out there and cycling (or running)? No way.
Remember why you cycle in the first place. It's to enjoy, and overcome, the terrain, the elements and everything that goes with it - good or bad, isn't it?
Cold and rain are the weather equivalents of the uphill grind. The sunny days are the free roll down the other side. In the words of George Michael - "You've gotta get up, to get down".