I hear South Africa's actually quite nice this time of year.
Regarding sustain,
There are several ways to build a guitar with great sustain. The neck configuration is key, as are the woods. Of course, there are pedals and other artifical sustain enhancers, but wood and neck configuration are what a builder can do.
Sustain is when the body of the guitar continues to vibrate. Denser woods vibrate more than lighter woods, so they have better sustain. Maple, and ash are some of the denser "standard" woods. Also, the less there is to obstruct the vibrations, the greater the sustain is. A 2 peice ash Strat has much better sustain than a 5 peice alder one. Likewise, a Les Paul with a 1 peice maple top has better sustain than a 2 peice plain mahogany LP.
This is where the neck configuration comes in. When a string is hit, it vibrates the length of the guitar, and the less there is to get in the way, the longer the vibration lasts. So a bolt-on neck, which is tightly bolted to the body, but still bolted nonetheless, has worse sustain than a set neck, which is bonded to the body like the peices of the body are bonded to each other. But the style of neck with the best sustain is the neck-through style. It's the hardest to fix in case something goes wrong, but the string is vibrating along the same peice of wood from nut to bridge. And that produces the best sustain of all.
There's also a rumor the the weight of the headstock can affect sustain?
Here.
Hope this helps!