I have needed to change several of my basal rates in the last few weeks. This is mainly a result of my changing exercise patterns. During much of January, I was running 3-4 times a week. This month I have been averaging 2-3 runs a week. Despite the lower number of runs, the total distances I am covering each week is staying constant because of my long weekend runs. Lately, those have been over half-marathon distances.
As far as my body is concerned, I guess that means that the number of runs is the more important factor. I have needed to change my basal rates for both daytime and overnight. These rates had all dropped about 30-35% at the start of January when I was really active. The recent rebound has seen them go back up about 10-15%.
It will be nice when winter ends and I can hopefully be a little more active.