Since I have had my Apple Watch I've found it nice and cool in the morning when sitting on the charger until a couple of days ago and then on one particular morning it was fairly toasty. The previous night I just happened to forget to charge my iPhone and as I'd just moved house and we had a nice 'NoFi' network the Wireless was turned off on the phone leaving all comms by Bluetooth and the phone was in my jeans pocket near the watch. I'm wondering, if this maybe kept some extra activity going on the watch that it could have really done without whilst it was charging and prolonged the charging cycle - it was still at 100% that morning but maybe it only just got there... other theories could be related to the charging coil being used as an antennae for some comms but I guess I'll have to wait and see on that one. Basic connectivity now at home means that Wifi is turned on on the phone so it will be interesting to see if there is any difference in the watch next time it charges. Similar observations anyone or are yours consistently cold or hot..?