Alternative excercise to biking Are there any alternative exercise to biking while it's raining?

I have been fortunate enough to solve my insomnia with biking...something with it seems to connect and works well to solve my ages old problem of sleep.

The part that helps me most is climbing hills, not so much the flat parts.

Jogging, walking, etc. somehow DO NOT seem to have the same effect in my case.

I am wondering what I will do when winter comes in and it  starts raining... any suggestions other than buying a costly stationary bike?
You can train inside your house with a trainer stand. Is quite cheap compared to stationary bike and it can be stored more easily.