I know this has been a recurring topic and almost everyone knows that speed, temperature and terrain are key factors on the EV estimated range, but I would like to add a couple of observations out of my 2.5 years of driving the Clarity. First I noticed that driving on a highway against strong winds would markedly reduce EV and also fuel mileage. Then I moved from LA to Las Vegas and immediately noticed that my GOM slowly crawled up from 50-52 miles to 63-65 miles, and stayed there for a while, without significant changes from January (temperatures on the 40's and 50's) to July (with a 117F record broken). However, after my first visit to a Las Vegas dealer for routine maintenance (an awful experience that I would tell elsewhere) I noticed that the GOM fell sharply from the 60s down to 47-48. First I suspected some sort of 'electronic reset' brought it back to the 'official' 47 miles, no matter how slowly I drove. However, I got an intuition and checked the tire pressure. They set it up all tires at 32 PSI, way down the recommended 36. So I reinflated the tires and voila! Good old GOM went back to the 60's in 3 days! So here's another variable to consider when trying to understand the GOM.
It’s possible that the dealer had your car ON/READY for a period of time which drained the battery a bit, while going zero miles. Similar to sitting in the car with the A/C on for half an hour. 36psi is the recommended, minimum, pressure for the vehicle at GVWR, or roughly 5000lbs. With one or two people in the car, 32psi would be a suitable pressure. It won’t harm the tires to run them at 36psi, even if a majority of driving is done with only one person in the car. Interestingly, Michelin has given the tire a maximum pressure rating of 44psi, however the maximum load rating is obtained at 36psi. The EV range estimate is worth its weight in charcoal. The difference between 32-36psi, probably isn’t much of a factor.