Whoops, my bad when doing the transformation. It won't work that low, only down to 20degC and at that point it probably approaches 1. Lucky me, the temps never

Whoops, my bad when doing the transformation. It won't work that low, only down to 20degC and at that point it probably approaches 1. Lucky me, the temps never dropped to under 19degC in the last 20 years in my area. So I'm probably going to be fine.