How can I tell in each month, when here will be no moon shining or seen at night?
A new moon (when the moon is not seen at night) happens regularly, every 29.5 days (roughly). This is roughly one day less than a month. So you can forecast the next few new moons by "add a month, minus a day"
The next New moon will be on 16 April. We would then expect new moons on: 15 May, 14 June, 13 July, 12 August and so on.
A website like timeanddate.com will do the accurate calculations for you (adjusting for your local time and so on.