But for rains, is it random or are there requirements that must be met?
https://help.stake.com/en/articles/4942138-stake-promotions-and-bonusesYou can check above link to know the requirements to be eligible for any bonus including rain in stake. In short, yes there are 2 requirements to be eligible for the rains. First is to wager 4k during the last 7 days and second requirement is verification level 2. Coming up to bonus drops in telegram, the requirements are always being informed along with the bonus drops.