The allusion that it will rain every big event.

There is no specific allusion to the phrase "it will rain in every major event", but it is just a common weather phenomenon. When people encounter important occasions or events, their emotions will be affected, leading to some physiological reactions in the body, such as sweating and rapid heartbeat. These physiological reactions are similar to the weather conditions of rain, so people will mistakenly think that rain is the function of some mysterious force or supernatural phenomenon.