When I play as the Swamp faction and see several piles of sulfur behind regular guards on day 111, it usually means that Hydras will appear in the first week... It's a pretty reliable sign. :) But in general, I don't know, it seems like few people believe in omens, but I remember in 11th grade, I saw ordinary girls walking to take a difficult final exam in the morning, and suddenly, right in front of them, a cat ran out of the bushes and crossed their path. They immediately turned around and went another way, even though they didn't seem like the type to believe in omens... And I also remember we were walking, and a cat tried to cross our path three times right in front of us, as if on purpose, but we chased it away each time.