Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Adelaide to Crete as you normally would.
In Adelaide, there will be less rainfall in Adelaide compared to Chania over the next 7 days.
You can imagine temperatures to be in the 31 °C range in July. The weather in Chania is generally hotter than Adelaide's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.