Umbrella Today?
Umbrella Today? is a super simple site that falls into the category of “I wish I made that.” You put in your zip code and it tells you weather you need an umbrella in a simple yes or no. Funny enough I left this comment in response to a post about the same idea involving pants a few weeks ago, “I actually think there could be a whole series of these. I wanted one specifically for umbrellas as well. Shouldicarryanumbrellatoday.com …”
They came up with a better domain than me (and I still think you could come up with a whole series of these for different stuff).
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They should have one that says if it’s hoodie day or not; being new to the US and from the tropics, I’ve gone out on some days and almost frozen to death