Cinderella time (midnight) or later is a good time to practise.
This is because the world around you is quiet and if you are in any way sensitive to energy you will note the difference.
John Kells used to practise in the middle of the night for this reason. Of course it helps if you don't have a 9 - 5 job.
The phrase " Cinderalla Time" is courtesy of the Kinky Friedman detective novels.