"What is night for all beings is the time of awakening for the self-controlled; and the time of awakening for all beings is night for the introspective sage." BG 2.6
It could be said that any time of the day is the best time of the day for connecting with transcendence - remembering you are not this body, and meditating on the sweet love of the soul that is the essence of Krishna consciousness. However, when Prabhupada was asked what is the best time for chanting japa, meditating on Krishna's name, he replied, "The hours before Mangal Arati."
When I heard Prabhupada's 'best time' response, I decided to try it. Mangal Arati is the first worship ceremony and kirtan that happens at the temple at 4.30am everyday. So the best japa time would be the hours before then, say between 2.30am to 4.30am.
These predawn hours have to be among the most beautiful and powerful, especially during warm summer nights where sounds of crickets, owls and other night creatures along with the low lying stars create a soothing background. There is a blanket on the noise of everything else and the sound of Krishna's name holds the space with little competition. Even the over-active mind seems to respect this time and put it's hankering and lamenting on pause for a while.
Often our life is so busy that our spiritual practice is just another 'to do' on an endless 'to do' list. Early morning hours don't feel like this. I have come to love this time, where the simplicity of the practice of quiet chanting and hearing shines like the stars above. One short mantra, beads to hold onto, and nothing between you and Krishna.
I also find these hours put life in perspective. The Vedas teach that the cycle of birth and death is like a ferris wheel, going round and round without stopping. Early morning hours slow me down, and seem to also slow the ferris wheel. I am reminded that to break this cycle of birth and death I'll have to want to do so. I'll need to hold on to someone to step off and I'll need to be ready to do that at the time of death. It's a serious challenge, this practice of bhakti yoga. In the dark and quiet of night, with Krishna's name, this seems desirable and doable.
If you can access these hours from time to time, there is nothing but gain to be had there. Even if you collapse back into bed for a nap afterwards - I guarantee you will rest better and be better!