Ordinary coolish 19C ambient temperatures.
I don't think it was hit by anything... it is a very symmetric series of cracks. No evidence of an object striking the screen.
Rubber replaced a year ago. Original glass I think ("Toughened")
I guess it must have been under stress.
Any recommendation who to get a replacement from? I will have to import from the UK. I have usually bought from EMS, they seem to have reasonable priced laminated screens.
Thanks[frame]