Read a ton of different sites and then mentally filter for hype.

Also, depends on what you are looking for. If you want to work at a "hot" startup, by the time you heard of them you are probably out of the really good equity opportunity.

If you just want to know what's is up and coming then I would focus on developer user groups and code sites where people will share examples of their work. A lot of startups start out as "hey, I built this this cool little thing..." and then grow based on word of mouth and social use.

I love PH, but I'm not so sure that's a good indicator of the hottest startups. A good amount of the hunts are just standalone products with no business around them.

Depends on what you mean by 'hottest' really. Newest? Fastest growing? Most novel? Most cutting-edge? Most recently funded? Other?

"Located in areas with the highest average temperature"?

Probably startups with the hottest funders.

Sorting profiles for current Founder/Co-Founder titles on Linkedin yields some interesting gems.

Isn't that what TechCrunch is for? [joke]