Question: [Wednesday, 6th Kisleiv 5783]
Is the earliest time for Davening Mincha Gedola calculated as 30 minutes past midday, or as Shaos Zemaniyos. I am asking because I noticed in the calendar that they calculate Mincha Gedola as 30 minutes past midday throughout the year, and it does not change.
Ideally, we follow Zemaniyos hours also regarding the 30 minutes after midday, and hence there will be times throughout the year when one is to wait more than 30 minutes after Chatzos to Daven Mincha Gedola, and times of the year when one waits less than 30 minutes after Chatzos to Daven Mincha Gedola. Nonetheless, many are accustomed to always wait a minimum of 30 minutes after midday in the winter months, as a stringency, even though the zemaniyos minutes are less.
Sources: See Rama 233:1 that the times of Mincha Gedola and Ketana are Zemaniyos; Admur 89:2 [that the main time of Mincha begins immediately at Chatzos]; Kaf Hachaim 233:6; Poskim who rule to follow Zemaniyos minutes for the 30 minutes: Shaar Hatziyon 233:8; Halichos Shlomo 13:1; Sheilas Shalom 1:18; Poskim who rule to always wait minimum of 30 minutes: Sefer Nivreshes p. 31 as Minhag Yerushalayim; Poskim who are stringent in winter to count as 30 minutes: Luach Eretz Yisrael Tukichinsky; Piskeiy Teshuvos 233:1