Question: I will be visiting Eretz Yisrael during Cheshvan / November. Do I say vesen beracha or vesen tal umattar?
Answer: The Shulchan Aruch (OC 117:1) writes that in Eretz Yisrael we begin saying vesen tal umattar (prayer for rain) in the beracha of barech aleinu from the 7th of Cheshvan. In chutz la’aretz, we don’t start saying it until the 60th day of the tishrei season. As this season begins on the 7th of October, we begin saying vesen tal umattar during maariv on the 4th or 5th of December (See Taanis 10a). We continue saying this until pesach.
The Shulchan Aruch (OC 117:5) writes that one who forgot to say vesen tal umattar after this time must do so in the beracha of shema koleinu. Failing that, they’d have to repeat the shemone esrei.
The Mishna Berura (117:5) quotes different opinions as to what someone visiting Eretz Yisrael during this time should do.
The Pri Chadash and Pri Megadim write that providing one is planning on returning within the year, they should follow their own community. Thus, one paying a short visit to Eretz Yisrael would continue to say vesen beracha until the 4th / 5th of December.
The Birkei Yosef, however, writes that those visiting Eretz Yisrael should say vesen tal umattar.
While R’ Yitzchak Yaakov Weiss (Minchas Yitzchak 10:9) and R’ Ovadia Yosef (Yechave Daas 1:73) agree with the Birkei Yosef, R’ Shlomo Zalman Auerbach (Halichos Shlomo, Tefilla 8:21) and R’ Moshe Sternbuch (Teshuvos Vehanhagos 2:55) hold that if they are staying in Eretz Yisrael until after the 4th / 5th December then they should say vesen tal umattar. One paying a shorter visit should say it shema koleinu (See Rivevos Ephraim 4:255).In conclusion, the Ishei Yisrael (23:37) writes that if one plans on returning before the 4th or 5th December, they shouldn’t adopt start saying vesen tal umattar early. If one doesn’t plan on returning until afterwards, they should say it in shema koleinu. Many sefardim will say vesen tal umattar even if only paying a short visit.