incrediBILL - 10:59 pm on Jun 30, 2012 (gmt 0)
Is there some reliable method to determine a Hawaii location by IP?
I'll ditto G1's answer: NO!
You can get close but no cigar.
The timezone suggestion is actually pretty good for Hawaii, nice to see people thinking outside the box.
What's more likely used even by Maxmind to narrow down the results to Hawaii is the whois records and reverse DNS results which would most likely be used to narrow down local service providers.
For instance, services like Comcast, Road Runner, etc. typically has the location coded in the reverse DNS of the IP address.
Put the JS in the <head> of the page in the so it should execute before the rest of the page displays. You only have to do this once before you tag it in the session as a Hawaiian timezone so it's really not so bad IMO.
I'd also back it up with server side GeoIP testing so if you can accurately detect it in some cases server side you get better results.
Once you get a big enough sampling, maybe Maxmind or someone will be interested in buying your Hawaiian GeoIP data from YOU! ;)