Question: Can I open and close the hood on my baby’s buggy on Shabbos? Is it okay to put a rain cover over the hood?
Answer: The Shulchan Aruch (OC 315:1) writes that Chazal forbade making a temporary ohel on Shabbos. The Gemara (Shabbos 138a) writes that one may unfold a folding chair on Shabbos. While doing so creates a shelter over the space underneath the chair that is not considered making an ohel. Thus, it would be muttar to open buggies and foldable cots on Shabbos (Shemiras Shabbos Kehilchasa 24:23)
R’ Yechezkel Landau (Noda B’yehuda OC 1:30) writes that umbrellas are not included in this category and may not be opened or closed on Shabbos. While many Acharonim (Chasam Sofer OC:72; Tiferes Yisrael, Kilkeles Shabbos, Ohel) disagreed with R’ Landau’s arguments, they did not allow their use.
Following R’ Landau, R’ Moshe Feinstein (Igros Moshe OC 4:105:3) and R’ Ovadia Yosef (Yalkut Yosef, Shabbos 2:p536) write that the hood may only be closed (unfolded) providing it is already open a tefach as no new ohel is being created. Likewise, when opening (folding) the hood, one should not open it fully, though leave one tefach closed to avoid dismantling the ohel.
The Chazon Ish (OC 52:6) compares buggy hoods to sukkah roofs which the Rema (OC 626:3) allows opening on Shabbos. As the hood is already attached to the buggy, one may open and close it fully on Shabbos. Most contemporary Poskim follow this view (See Rivevos Ephraim 4:97:97). R’ Yehoshua Neuwirth (Shemiras Shabbos Kehilchasa 24:13) and R’ Ribiat (The 39 Melochos p1079) write that if the buggy’s canopy is closed one may spread a rain cover on top.