Well im glad to hear this has happened to someone else.
This has happened to me on numerous occasions over the last 6 months. Only difference is that the fob does not always unlock the vehicle.
Sometimes I can unlock the driver door but clicking the fob again does not unlock the other door. I end up having to press the unlock button on the dash or manually open the passenger doors by pulling on the interior handle.
Temperature does not seem to matter for me. Sometimes it's hot...sometimes it's cold.
Does not appear to be a battery issue as it will work fine for weeks on end after failing.