Today is “leap day,” the bonus day that appears at the end of February every four years to help correct the calendar – so we aren’t eventually welcoming Spring in August. But that’s on the Gregorian calendar, which is a solar calendar and the one most of us use.
What about the Hebrew calendar, which is lunar?
The Hebrew calendar is a bit more complex, being a “lunisolar” calendar that simultaneously is dependent upon cycles of the moon to measure months and cycles of the sun to measure the lengths of the day and the year. This might not intrinsically be such a big deal, but when your religious obligations include blessing and sanctifying each new month, it’s pretty important to get the timing of the months correct.
. . . the problem with strictly lunar calendars is that there are approximately 12.4 lunar months in every solar year, so a 12-month lunar calendar is about 11 days shorter than a solar year and a 13-month lunar calendar is about 19 days longer than a solar year. Strictly followed, the months would drift around the seasons, and the month of Nisan, which is supposed to occur in the spring, would occur 11 days earlier in the season each year, such that over time Pesach would be celebrated in all four seasons.
So in the same way that the Gregorian calendar adds an extra day to February every four years, the Hebrew calendar intercalates a complete month over the course of a 19-year cycle, called the “Metonic” cycle, so that the lunar calendar realigns with the solar years.
So, the short answer is yes, there is a leap day on the Hebrew calendar. The Forward explains the full answer here.