Bright Sky in the Middle of the Night

I had too much tea last night.  I was also very tired and slept early before 10 pm.  The combination makes a recipe for waking up in the middle of night at 4am.  I was surprised by the bright sky.  It was something that we missed usually since we are in dreamland at this time normally.  Then it drizzles and the sky turned dark again.  This phenomenon brought back memories of living in Canada.  I had the same observation before except the sky is a lot brighter there.  I thought the earth rotation has changed with I first noticed bright sky in the middle of night.  Now I know it is just electrical discharge.