Same here, I live in Venezuela and here weather is hot all day long. I'm starting to stop shampoo since I had a dandruff "attack" last week and I never had something like that before, not even dandruff.
Here is hot (past 27°C always) and it's hard to try this method since I'm sweating every day if I'm out.
I have now 12 days without shampoo and the dandruff and the itchy is harder than ever. Any tips?