Is your actual range dropping or is your Guess-o-meter learning how you drive and the conditions outside?
See:
www.lightningowners.com
See:

Don't trust the GOM! Best ways to calculate how far...
In EV forums there are always lots of new threads popping up from first time BEV drivers who are all worried or worked up because their Guess-O-Meter (GOM) is showing much less range than they think it should. This will especially happen in colder weather when the range drops. For new EV owners...