Using the UV Index in Sunburn Season ☀️
The post below was sent as an issue of my newsletter, Ready for Rain.
People sometimes get confused when they see Sachi on a sunny day in long sleeves and pants. They wonder why she sits in the shade when everyone else is in the sun. “Aren’t you from Hawaii?” they ask. “It seems like you’d love the sun”.
Invariably, Sachi has to explain that being from Hawaii is why she stays out of the sun. She witnessed what it does to the skin over time and vowed not to be one of the casualties. As long as she keeps getting carded when buying alcohol, I will assume it’s working.
I didn’t grow up on a tropical island, but I did get my share of the sun at Lake Norman and North Carolina beaches. I sometimes feel nostalgic about those summer days when we’d finally go into the cool darkness of the house to let our pink skin rest in front of a fan. I can still feel that burning sensation when taking a shower with sunburn. Those days are now gone and I try to be more responsible with the sun and not get burned. Maybe one of the reasons we both love the pacific northwest is that the sun is less of an issue.
My family’s perception of the sun was like everyone’s at the time: when the sun is out, it can burn you. Sunrise to sunset, it’s always powerful. Only recently have I learned that the skin-burning power of the sun changes significantly throughout the day, and the seasons. And now, knowing its power is a simple matter of knowing where to look.
The UV Index
In my daily weather watching, I track all the normal data like temperature, precipitation, wind, humidity, etc. These help me plan my day and dress appropriately. I recently added a new data point to my weather watching that has transformed how I think about summer days. It’s called the UV Index and I encourage you to track it, too.
The UV Index is an hour-by-hour measurement of the sun’s skin-burning power, at a specific time and location, on a scale from 0-11 (or more). The index was developed in 1992 but is only now becoming a standard in weather apps and websites.
Let’s imagine a family who is planning a day at the beach. The parents are concerned about sunburn but would prefer not to use sunscreen, if possible. Instead of just guessing or getting burned, they can use the UV Index to understand the sunburn risk on an hourly basis. Maybe 11-2 is time for a movie or nap.
It’s easy to assume we humans can tell when the sun is dangerous. It may seem the UV Index data is just a backup. After all, most people know the sun is most powerful during the middle of the day. But what about seasonal change? Elevation? Cloud cover? These are all factored into the index.
We were camping with a group a couple of years ago on a warm fall day. The sun was bright and seemed strong. Some members of the group applied sunscreen accordingly and we noticed. It was a logical move based on a lifetime of experience. Having learned about the UV Index, I thought to myself, “That sunscreen is wasted. The UV index is at ‘3’ right now and getting lower; no one is getting burned.” Rather than trying to awkwardly explain the index and how to use it, we just sat back with the confidence of someone with data on their side.
That’s what’s so useful about the UV Index. It takes the guesswork and wasted resources out of the equation. In this example, the UV Index was low on a sunny day because it was fall. In most of the northern hemisphere, the UV index remains low through the fall, winter, and early spring. Again, hooray for the “north” in “pacific northwest”.
Where to Find UV Index Data
Tracking the UV index is easy and free; you just need to know where to look. For example, the weather app that came with my iPhone displays it on the same page as all the other weather info.
I also use a free app called UV Lens that provides two day forecasts and a nice interface. (Find the app for Apple, Google)
Using the Index
The UV Index uses a standard scale that relates to recommendations about sun exposure.
The Environmental Protection Agency also has a few handy resources if you’d like to know more:
I think we should take the sun and its UV rays more seriously and that’s the real message here. Today on Orcas Island the UV index reached 5. In Honolulu, it got to 10, and at Lake Norman, 8. Interestingly, the peak times vary by latitude. Since Honolulu is closer to the equator, it peaks closer to noon. On Orcas, it’s closer to 2pm.
The index is a great tool, but it’s up to you to decide what to do with the information. Sunscreen is an option, but be aware that there is growing evidence that it’s harmful to marine life, like corals. If you go snorkeling, consider covering up instead. That’s really the best way to avoid the sun: blocking it with hats and clothes that filter out the UV rays.
If all else fails, you can watch the index number go down while having a glass of wine with Sachi in the shade.
I write books and run a company called Common Craft. I recently moved from Seattle to a rural island. Here, I write about online business, book publishing, modern home construction, and occasionally, dumb jokes. 
