"There are some people who might have better technique than me, and some may be fitter than me, but the main thing is tactics. With most players, tactics are missing. You can divide tactics into insight, trust, and daring." - Johan Cruyff
This is a bit of an exaggeration. Playing in heat only takes a week or so to adapt to. There will still be time before the season starts. There is a lot you can do to pre-acclimatize as well, like training in layers to get your body temperature up. I don't think it's an issue.