The Shulchan Arukh discusses the law of one who accidentally requested rain in the summer in OC 117:2-3. He rules that if that happened in a country that didn't need rain at the time, the prayer must be repeated; however, if it happened in a country that indeed needed rain at that time, the prayer need not be repeated (but it can be repeated voluntarily).
Thanks to Joel K for this link
Rabbi Shlomo Zalman Aurbach Zatzal answers that when the people come for Sucos they are wearing summer clothing and can't handle the rain, and therefore we delay until 7 Cheshvan, however whe they come for Pesach they are wearing winter clothing and can handle the rain.
Rabbi Yosef Shalom Elyashiv Zatzal answers that to stop ...
Wow. Just saw this over Yom Tov. Rav Avigdor Miller on Tefillah, just published (2021), by R' Yaakov Astor, quotes from his shiurim. [He says in the introduction that some of the quotes were lightly edited. I couldn't tell which shiur exactly it came from.] Anyhow, p. 127:
Question: In P'sukei D'zimrah there are so many selections from
Tehilim, and the Rav ...
R Yisroel Reisman in his book Pathways of the Prophets asks exactly your question (p. 440) and answers
In a previous life, Reuven may have lived as Yaakov. Today Yaakov is
no longer alive. Still, Yaakov's enemies may be speaking lashon hara
about him, even today. A person should want to forgive even these
sins. Thus, each and every day he forgives anyone ...