This year, it is actually the Jews that are one month off. I found this on http://www.studiesintheword.org/jewish_calendar_errors.htm
Why the Jewish Calendar will be Incorrect in 2016
This article explains why most observant Jews and others following the Jewish calendar will be celebrating God's annual Holy Days one month late in 2016.
In trying to follow Exodus 12:2, Exodus 13:3-4, 7-10, and Numbers 9:2-3, Judaism says that Passover, which they celebrate on Nisan 15 rather than on Nisan 14, must not fall before the northern hemisphere spring equinox (Tekufot Nisan). The spring equinox currently occurs each year on March 20th or 21st and is that time when day and night are of approximately equal length. The spring equinox establishes the first day of spring. It is a solar, not a lunar, phenomenon.
But current Jewish calendar procedures periodically conflict with the use of the equinox to establish the first month of the religious year:
In 2016, Nisan 14 (Passover) can fall on March 22, the first opportunity for the 14th day of a Biblical month to occur after the equinox. But the Jewish calendar sets Nisan 14 at April 22nd. Why? Because the Jewish year 5776 (the spring months of 2016 fall within the Jewish year 5776) happens to be the 19th year of the 19-year calendar cycle and is then, by Judaic definition, a leap year (the 13th month must be added). This forces the first month to begin one month later than it normally would. Unfortunately, their calendar leap year tradition is so rigid that they fail to follow what we agree is the correct interpretation of the scriptures listed above, that God gave them, which strongly imply that the Passover must be kept at the first opportunity on or after the spring equinox.
What allows them to ignore their own calendar rules? One reason they feel free to adjust the calendar to their liking is because Leviticus 23:2 and 4 are interpreted by Jewish Oral Law as saying that the people are allowed to keep the Holy Days on whatever day is most convenient.
It should be pointed out that the Jewish calendar leap year designations are NOT Biblical.
Let's add a little more detail: The spring equinox occurs on March 20th at 4:40 PM, Jerusalem time. The Jewish calendar calculates the new moon of Adar II (the 13th month of the previous religious calendar year) to be at 9:31 PM on March 8th and, due to the postponements of the previous Tishri 1, March 11th as the first day of the month. Either day will place the 14th day of Adar II on or after the spring equinox and thus the month should be Nisan (Abib), not Adar II. The result of this error is that the Jewish calendar is ONE MONTH LATE from March 2016 through March 2017! By making 5776 a leap year, they ignore the fact that, by their own interpretation of the Torah, Passover must be observed at the first opportunity on or after the spring equinox. This is the way the lunar calendar is kept synchronized with the solar calendar, and is an essential part in keeping the Passover (and every other Holy Day) in its season.
But some may wonder why it matters when Abib occurs, as long as it is in the spring. One of the major justifications why Abib should be assigned to the first qualifying month relative to the spring equinox is that there needs to be a consistency between years so that crops will be in approximately the same stage of development at the same time each year. The importance of the maturity of grain for the wave-sheaf offering (Lev. 23:9-14) is obvious. Another reason is that the one month delay will push the Feast of Tabernacles (Sukkot) too late and too close to the Israeli fall rainy season. For this reason we should avoid delaying Abib until the second month after the equinox as the Jewish calendar does in 2016. It is peculiar how the spring equinox is called "Tekufot Nisan", but when a conflict with the designated leap year occurs, the equinox is forced to fall in Adar II, not Nisan.
The Church of God Most High believes that the first day of every month must begin at the true conjunction of the sun and moon (the new moon) and that Passover (Abib or Nisan 14) must occur at the first opportunity on or after the spring equinox. That places Abib 1 on March 9th and Tishri 1 on September 1st. The result of all this is that in 2016 the Jewish calendar will keep the holydays one lunar month late.