For important things like this (or planning one's wedding, which is how I found it), I suggest The Old Farmer's
Almanac. Looks like you can set the site for wherever you are or are going to be for the current week (not ALL that helpful!), but you can also find the small, Reader's Digest-style bound books in checkout aisles at groceries. Not expensive, either! Also looks like there is a digital version of the almanac.
I found it well worth the couple bucks (if memory serves) just for the sunset info, but it also has lots of fun info throughout it!