Sun exposure in Hawaii is not a joke. Visitors to the islands suffer from painful sunburns on the first day of their vacation and it can make the rest of the week unpleasant. Sunscreen is important!
Sun Exposure in Hawaii Means Direct Sunlight
We all know how the Northern Hemisphere of the Earth tilts towards the sun during the summer months and away from the sun during the winter months. Hence, there is far more direct sunlight for Northern areas during the summer. Hawaii is on the equator, so it has the same amount of direct sunlight throughout the year. People forget that while traveling to the islands in the winter months, it is not going to be any less direct sunlight than if you were there in the summer. Although there may be heavy rains and storming, the direct sunlight is just as strong, even on a cloudy day. This is why it is important to wear sunscreen, even on a cloudy day!

Cloudy sunset by Daniel Ramirez is licensed under CC BY 2.0. Image may have been resized or cropped from original.
Cool Breezes Distract from the Heat
At the beach, the trade winds keep you cool on the sand. It prevents you from overheating in the hot Hawaiian heat. At the same time, it distracts you from the sun exposure in Hawaii! It can be easy to dismiss the fact that you are in the process of sun burning because the ocean breeze is keeping your body fairly cool. Do not let this serve as a furtive distraction. Be aware of this phenomenon and go to the beach prepared. I suggest applying sunscreen before even stepping onto the beach. By doing this, it allows the sunscreen to dry before getting in the water! If you apply sunscreen right before hopping into the ocean, it typically washes off easily. Even the sun lotions claiming to be “water resistant,” wash off within a few minutes of a dip in the ocean.

Waikiki is typically seen as the “tourist” area for O’ahu.
Palm trees by Orcrist is licensed under CC0 1.0. Image may have been resized or cropped from original.
High UV Index
Hawaii has a typically high UV index at all times of the year. According to daily UV reports and Hawaii Pacific Solar, the islands average 6-7 for its UV index in the winter and 11-12 for its UV index in the summer. The UV index scale is rated on a scale of 1 to 15, with 15 being at risk of overexposure. This is something to keep in mind, especially for those traveling to the islands having had minimal sun exposure prior to their visit. Many come to the islands with the hope of tanning quickly and easily within a few days of their vacation but that is usually not the case.

Hawaii 2013-09-19 (124) by Armin Rodler is licensed under CC BY-NC 2.0. Image may have been resized or cropped from original.
First Day Burn
The first day burn is a result of the disillusioned visitors who aim for a dark, bronzed tan within 24 hours of touchdown on the islands. These visitors typically disregard sunscreen and go straight to the tanning oils, which are usually not helpful in these situations. Skin that has not been exposed to such high UV indexes on a regular basis is prone to burning. This is why most tourists burn the first day and walk around with red sunburn marks. It can be very painful, and I recommend avoiding it. Also, burning off the top layer of skin makes it more difficult to tan as it will take a week or two for the skin cells to slough off, allowing to tan the layer underneath.

Secret Revealed by Randy Robertson is licensed under CC BY 2.0. Image may have been resized or cropped from original
I didn’t even spend more than a day just walking around Waikiki for the first day of a 10 day trip, and my face got so badly sunburned my forehead, cheeks, and eyes were swollen beyond recognition the next morning. The UV exposure on the islands is no joke.
I’m sorry to hear you had to experience that.
Thanks for the reasoned answer, but 20 degrees North of the equator is ~1500 miles, so let’s say you are closer to the equator than the mainland.
Hey Peter! Don’t forget to mention the different Sunscreens that are available. The ones from the Mainland are typically TOXIC to the Ocean Eco Systems as well.
Especially the Reef Life! Please stress how those two components in the sunscreen lotion kill life in the ocean. And name the components that are now BANNED IN HAWAII. But remember most Visitors will bring the wrong kind with them. We need to discourage them from that don’t we?
Thank you Kevin for adding your voice to this!
Plus, applying sunscreen just before the exposition doesn’t work, because most of the commercial sunscreens are chemical sunscreens. They don’t start to be fully efficient after about 25-30 min of applying them on! Mechanical ones : The ones that make you look white with zing and titanium oxides, are efficient right away though, but they will rinse off faster. However, I still recommend using the later ones, because the chemical ones, with nano-molecules (so you don’t look white with the cream on), are highly carcinogen and highly destructive of the fauna and flora in the oceans (it’s kills the coral, for example). But yup, don’t underestimate the sun in tropical areas!^^
wow thanks for the deeper science here!
Very kind and considerate of you to share this, and I also appreciate the science of sun exposure, warnings, and geography lesson.
You’re welcome!