This week we are reading Parashat Balak, but our friends and relatives in Israel are reading Pineḥas. What gives?
Well! It was very sharp of you to catch that difference! It has to do with the celebrations of the various festivals. When a festival falls on Shabbat, we read the Torah portion associated with that festival.
In Israel, they are observing only one day of each festival, rather than the two we observe here in the diaspora - intended for us to be certain we are celebrating during the times when the festival is being celebrated in Israel.
The disparity comes when the second day falls on a Shabbat. Then we are reading the parashah associated with the holiday, but the Israelis have moved forward with the next week’s reading.
On April 13th, we all read Parashat Metsora. During Passover, on Day 1 we all read the Passover portion. But on April 27, in Israel they were reading Aḥarey Mot while we were observing Passover Day 8 (not observed in Israel). We didn’t read Aḥarey Mot until May 3rd. So we have been behind.
When will we catch up? In Israel they will read Parashat Matot on July 27th and Parashat Masei on August 3rd. We will read a combined Matot + Masei on August 3rd, and thus once again be lined up with our family in Israel. Some years we combine Behar and Beḥukkotai to catch up. If there is a divide after Shavu’ot, we would combine Ḥukkat with Balak.
There are 54 parashiyot. We are reading in the triennial cycle, which means generally that one year we read the first part of each portion, the next year we read the second part, and the year after that we read the third part. (This practice goes back to ancient Israel.) Additional rules followed since were codified in the sixteenth century in the Shulḥan Arukh (Orakh Ḥayyim 428), including the days of the week on which certain holidays may not fall, etc., and also including which parashah should be read when. On the Shabbat before Pesaḥ, e.g., we must read Tzav, unless it is a leap year in which case it would be Metsora; however, if Rosh Hashanah was on a Thursday, it would be Aḥarei Mot.
And if there are 54, how do we fit them all into 52 weeks minus holidays? Very carefully! Actually, Hebrew years can be shorter or longer than 52 weeks. And we read the 54th, Vezot HaBerakhah, on Simhat Torah.
In the end, we break even, and eventually everything gets read.