On April 8, erev (the day preceding) Passover, there will be the opportunity to perform a mitzvah that last presented itself in 1981 and will not occur again until 2037. That mitzvah is to recite Birkat HaChama, the blessing said when one sees the sun return to its original position, as it was during the week of Creation. According to the Talmud in tractate Brachot (59b), this blessing is recited every 28 years, on the fourth day (Wednesday), when the vernal equinox falls in Saturn. (Chama means “sun.”)
Really, the Talmud discusses tekufat Nisan, the beginning of the spring season in halacha (Jewish law), which is several days after the astronomical vernal equinox. The astronomical vernal equinox typically occurs on or about March 20; the “halachic equinox” falls on March 25 of the Julian calendar, which is April 7 of this year, adjusting for the Gregorian calendar.
According to the Creation account in the first chapter of Genesis, the sun was created on Wednesday. The vernal equinox is considered the starting point of the sun’s creation. Since a solar year contains an extra quarter of a day, each year the equinox occurs six hour later. It therefore takes four years for the sun to return to its position at the proper time. As there are seven days in a week, it takes 28 years (4×7) for it to return to the proper position on the appropriate day of the week. The sun actually assumes its “starting position” on Tuesday evening, but one must wait for Wednesday morning when the sun becomes visible to be able to recite the blessing. (After each day in the Creation account, the Torah states, “It was evening and it was morning.” From this it is derived that Jewish dates start at sunset, with the result that Wednesday in Jewish law starts Tuesday evening.)
The blessing recited on this occasion is “Oseh maaseh bereishit,” that God created the works of creation. This is the same blessing recited when one sees lightning and other works of nature. However, because of the rarity of Birkat HaChama, additional prayers are recited to mark the momentous occasion. These typically include Psalms 19, 121, 148 and others. Also recited is a portion of the Talmudic passage from Brachot, which relates the source of the practice. Various relevant Biblical verses are also said, though there is no set text.
The blessing is recited after the morning prayer service, optimally at sunrise. However, the prayer may be recited until the third hour of the day. (In Jewish law, the daylight hours are divided into twelve equal portions called shaot z’maniot, which may be longer or shorter, depending on the time of year.) There are those who permit the blessing to be recited until midday, though it would be preferable not to rely on this unless circumstances do not permit Birkat HaChama to be recited earlier.
And if the Sun Doesn’t Shine:
If April 8 is cloudy, Birkat HaChama may still be recited so long as the form of the sun is visible through the clouds. If the sun is completely obscured, one should recite the prayers to mark the occasion, but not recite the blessing using the Name of God. (A minority opinion permits the blessing to be recited even if the sun cannot be seen; in such an event one should consult their local rabbi for guidance.)
Birkat HaChama should be recited outdoors, facing Jerusalem, east. Someone who is unable to leave the house, or who may be confined, may recite it from a window. This is true even on an airplane. The mitzvah is optimally performed in a large group of people because of the principle that doing so is greater praise to God.
This year, there is an additional wrinkle: Birkat HaChama falls on erev Pesach, Passover eve. This is an uncommon, but not unprecedented occurrence. It last occurred erev Passover in 1925 and before that in 1309. Because of this, the practice is for the congregation to not recite the entire text verse by verse as they normally would. Instead, only those verses that appear in the text prior to the blessing are recited verse by verse; those appearing after the blessing are recited individually. Additionally, on erev Pesach, a ceremony called a siyum, which marks the completion of a volume of Jewish learning, is typically held on behalf of the first-born males. This siyum, which is typically held after the morning service, should be made after Birkat HaChama.
There are other laws relevant for the optimum fulfillment of this rare mitzvah, though they would be beyond the scope of an article such as this. Birkat HaChama is an opportunity that might not present itself more than two or three times in a person’s life and it behooves us to do our utmost to fulfill this mitzvah to the fullest. Readers are encouraged to obtain one of several works available on this subject or to consult their own rabbi for proper guidance.