You could refer to it as a quarterly event.
The word - quarterly - means happening four times a year at regular intervals.
It is a triennial event. A triennial event happens three times a year.
lyphsucktion
An event of some sort that happens twice a year.
An annual event starts with A and happens once a year.
2 times a year
Something that happens once a year.
Biennial is a word describing an event that happens every two years.
There are 365 days in a non-leap year, so an event would occur 365 times in one year. However, if it's a recurring event that happens on a specific day of the week or month, it would occur fewer times depending on the pattern.
An annual event
equinax
An annual event occurs once a year.
yes i'm positive it happens every year