When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Kuala Terengganu is roughly greater than that of Gillette. You can assume this to be the case over the next 15 days.
You can imagine temperatures to be in the 33 °C range in April. The weather in Gillette is generally colder than Kuala Terengganu's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.