I took a raincoat with me to Singapore, as I'd heard that there are two seasons there, wet and wetter.
Turned out to be a mistake.
I didn't see a single raincoat the whole time I was there: not on a person, not in a store, none at all. Turns out they're too hot and stifling.
Instead, everyone carries an umbrella. Actually, everyone who wants to avoid getting wet, which is not the entire population: some large fraction seem to manage to get where they need to go by a combination of public transportation, underground mall and tunnel, or cutting through shopping malls or building lobbies.
In most of the world, the rules for safe jaywalking are a great example of local, tacit knowledge: I never try to cross against a light in London unless there are locals doing it. Why? Natives understand how drivers behave, how fast the cars go, how quickly they can stop, how likely it is that there will be cops around, and all the little variables that visitors don't; furthermore, they understand them well enough to be able to make correct judgments in fractions of seconds.
Since jaywalking is illegal, getting from Point A to Point B without having to get wet is the equivalent tacit knowledge for Singaporeans.
[To the tune of Eric Clapton, "Let it Rain," from the album "Crossroads (Disc 2)".]