Timezones
For every yowl or widdle protest there is always confusion about timezones. Often the times are stated in UK time.
Winter
Generally they happen at 9pm UK time, which in winter is 9pm GMT. There is an example yowl timezone equivalents set for a 9pm GMT yowl here.
Summer
Summer is one hour ahead of UTC/GMT, and known as British Summer Time (BST).
I have put in an example yowl time here, which gives other timezone equivalents for a 9pm (BST) yowl.
Eldrid Elephant 
So now I’m confused, are we going by GMT and howling when the clocks say 8 o’clock BST?
1600 hrs. That is when we’ll yowl.