If you watch her carefully, she should be okay. Try hard to keep her cool if she looks over-heated
I have 4 Shelties; we live in Whitby, Ontario, Canada. We have 4 seasons. My Shelties love to play outside all year. In the summer heat they will find some shade under a tree and not want to play as much as when it is cooler outside. In the summer on warm nights they love to go for a walk.
Hawaii has a rabies quarantine -- it takes about 6 months to get all shots/tests/blood work done to get them released upon arrival, or they are quarantined on Oahu for 30 days. If you did take your dog - please fly only in winter or at night, as it is very hot on the tarmac and in the plane after landing.