It's getting to be too hot to be in Hawaii in September because of Global Warming

Unless you have air conditioning in your rental car and hotel you really don't want to be in Hawaii anywhere in September if you are over 40 or 50 years of age. It's just too hot and humid now. If you are a younger person often if you have good health you can camp out places and swim (as long as you have a car or a bus to transport you places) (check which islands actually have buses by the way).

But, I'm 71 and having an air conditioned rental car and an air conditioned place to stay this time was necessary to feel okay most of the time. Even then I found myself almost passing out near Hanalei bay in a non-air conditioned bathroom where it was 85 to 88 degrees outside and likely still in the 90s or above in the bathroom at about 9 pm at night recently. So, if you are in your 70s you have to be really careful of the heat and humidity now in September. I'm thinking November to about May is a good time to come to the islands for better temperatures. Lately I was checking different islands regarding temperatures. The furthest North Island that tourists visit is Kauai. But, the day time temperatures have been mostly 85 to 93 or 94 degrees with about 90 percent humidity. But, on a northern island you might get temperatures in September as low as 72 to 73 degrees at about 6 am in the morning. Oahu and Maui might be the same temperatures in September (the daytime temperatures but the night time temperatures likely will be much higher. So, on further southern islands (The big Island is always the hottest). For example, even in January the water near Kona is often 85 Degrees on the big island or more which is what it was when I went there to snorkel in January 2015 with friends.

Recently I was snorkeling and either the water was too hot, the sun was too hot, or I was just bouncing around too much in the waves but it made me nauseas so I had to go into shore and get into a fresh water cool shower for washing off sand and salt at the beach there to cool down and regain my center which was good. It was a very hot day above 90 and the water likely was close to 90 degrees too where I was then with full sun.