I read if the environment is too cold or too hot, the zucchini will not flower properly. Zucchini will put out male flowers first until it fully matures, then the female flowers start coming. I used to get better fruiting but I was advised to plant more than one plant for better polination. This time I am going back to pic-n-pic yellow crookneck squash, I had better luck with that one before and it is similar to zucchini in use.
Happy gardening in Hawaii. Gardens are where people grow.