Are there months with two or no full moon?
We already know now that the moon month is mostly shorter than the calendar month, being on average approximately 29.5 days. If full moon falls on the first or second of a month, it is possible that another full moon occurs in the same month, for instance in July 2004:
Friday, 2 July 2004, 01:08:54 pm
Saturday, 31 July 2004, 08:05:06 pm
This event is also known as “blue moon”.
It occasionally happens in February that no full moon occurs, namely, when full moon happens to be right at the end of January. Because February, is an exception and shorter than the moon month, February full moon does not take place at times. Let’s look at an example in February 1999:
Saturday, 2 January 1999, 03:49:30 am
Sunday, 31 January 1999, 05:06:30 pm
Tuesday, 2 March 1999, 07:58:30 am
And if looked at closely, we actually have a double phenomena: in this case there is no full moon in February and simultaneously a “blue moon” (twice a month) full moon in January. This, by the way, is mostly the case, as one full moon at month’s end of January has to precede the February without full moon. This again causes an additional full moon at the beginning of January.