Historical Rules · 10 June 2022
Rule 502.2
Official source text from the 10 June 2022 Rules release
Second, if it’s day and the previous turn’s active player didn’t cast any spells during that turn, it becomes night. If it’s night and the previous turn’s active player cast two or more spells during that turn, it becomes day. If it’s neither day nor night, this check doesn’t happen and it remains neither. This turn-based action doesn’t use the stack. See rule 725, “Day and Night.”