Yosef Karo

“ Scholars should greet as if they are abandoned and excommunicated by God. If a non-scholar greets a scholar, he should respond with low speech and seriousness. Scholars alone continue to fast Monday, Thursday, and Monday until the spring equinox. They are permitted to eat at night, work, and do other things. They stop fasting for the beginning of each month, Hanukah, and Purim. After the spring equinox, when the sun reaches the beginning of the Taurus constellation, they do not fast more, because rain in that season would be a curse, given that there had not been any rain that year. ”

“ Similarly, if the time of Pesach or around there arrives, which is the time of the blossoming of trees in the land of Israel, and the rains have not fallen, they fast and cry out until rain for trees arrives or the season passes. Similarly, if Sukkot arrives and there has not been sufficient rain to fill the cisterns, ditches, and caves, they fast until there is sufficient rain for the cisterns. If there is no water to drink, they fast for the rains as long as there is no water to drink, even in the summer. ”

“ The whole nation assembles in the synagogue to pray, yell, and supplicate, just like on all fasts.
סעיף ב
הגיע ראש חדש כסלו ולא ירדו גשמים, בית דין גוזרין שלש תעניות על הצבור, שני וחמישי ושני, וכל העם נכנסים לבתי כנסיות ומתפללים וזועקים ומתחננים כדרך שעושים בכל התעניות.
574:3 If these fasts pass and there is no response [of rain] , the court decrees three more fasts on the community, Monday, Thursday, and Monday, and on these, they stop eating the day before; it is forbidden to do work during the day, though not at night ”