Confession time: I'm terrible at packing. Seriously, ask anyone.
PackingEssentials is a bonafide online packing tool that will generate a custom packing list based on weather, logistics and trip type. Because, it's a hell of a lot better than, say, trying to find the Czech equivalent of Target at 11 p.m. because you forgot socks. True story.
Enter some basic info about the trip–destination, dates, type of activities planned, accommodation, etc.–and PackingEssentials will generate a customized packing list. Though the interface is simple and intuitive to use, it's an extremely thorough tool to have in the arsenal. (In case you don't have any packing lists around.)
Packing for South America
This particular example assumes a five-day trip to Bogotá, Colombia.
See that weather info at the bottom? The site comes with access to a 16-day forecast, adjusting its algorithm accordingly. Speaking as the guy who forgot to bring a raincoat to Iceland (again, true story), I'm all about this feature.
Furthermore, I can select from three packing styles: minimal, normal and perfectionist. I went with perfectionist since it lists everything I could need. Those who like or need to travel light should go with minimal; it lists only absolute necessities.
PackingEssentials' list is interactive and well-organized. I can check off items one at a time in four main categories: preparation and documents, packing and accessories, entertainment and sundries along with clothing and footwear. Everything I could need based on where I'm going and what I plan to do. And I can save different lists for later if I sign up.
Essential items are in bold and black; less essential objects still recommended things are lighter in color. Extras and non-essentials are gray. Score one brownie point for color coding. It makes the whole process that much easier.
There is also a fifth category: destination information. It shows the daily weather forecast for my vacation dates and finds out if I need a travel visa. It also refers me to Booking.com if, for whatever reason, I haven't found a place to stay yet. (Though the assumption is that PackingEssentials makes some $$ from its relationship with Booking.com.)
The site is available on mobile as well, so there's really no excuse. I still might pack too many hats in my suitcase, but maybe I'll remember to bring items I actually need. Maybe.