BT Er 65a(28) :צריכא הילכתא צילותא כיומא דאיסתנא‏ : legal discussion requires clarity (of mind) like a day of the north wind
See the entire entry for hilkā, hilkəṯā n.f. accepted legal decision; custom

BT Er 65a(28) :צריכא הילכתא צילותא כיומא דאיסתנא‏ : the procedure needs clarity, as on a day with a northerly wind
See the entire entry for *ṣillū, ṣillūṯā/ṣīlūṯā n.f. mental clarity