The First Warn Outdoor Index

Here’s today’s First Warn Outdoor Index for Tuesday May 31, 2011

snapshot (3)

Here’s what it means:

Earlier this year I starting thinking about a way to help people to understand and deal with summer time weather. In particular kids going to the YMCA of Greater Charlotte summer camps. They had approached me about doing some summer heat education and safety talks. So I started to develop what I call the Outdoor Index. It takes 3 widely used indicies that are used most often during the summer months. The Heat Index, the Air Quality Index and the UV index. Now all of these can have significant impacts on your outdoor activities, but not equally in my onion. So I weighted them based on the biggest impacts to everyone.

The first is the Heat Index, which many people are already all too familiar with. This is your basic “Feels Like” temperature based on the combination of heat and humidity. This is the most important factor in the Outdoor Index because it affects everyone and really impacts your bodies ability to cool itself. Using the scale below I assign a numeric value from 1-10.


Next is the Air Quality index and a common problem when we get stagnate air masses during the summer months in the Carolinas. While I certainly don’t want to diminish the impacts of poor air quality. It most often only impacts those with poor respiratory health or the very young and old. On very rare occasions when it’s quite high it impacts us all. It gets the second highest weight in the Outdoor Index. Same as above a 1-10 scale is used to assign a value.


Last but not least in the UV index. Now everyone should be protecting their skin from the sun due to the increased risk of skin cancer. With that said the UV index on any given day during the summer is above 8 an often 10+. If it’s sunny you need to protect yourself. So not to constantly skew the Outdoor Index it was given the lowest weight. Plus no matter the number on the Outdoor Index you should always be safe and protect yourself form UV. It will be something I’ll try always mention in my forecast.


So after getting all those values above you use the formula below and you end up with our exclusive Frist Warn Outdoor Index.


So today is Tuesday and today’s Outdoor Index is a 6.4. This was based on taking a 106 AQI = 4 , Heat index 102 = 7 and UV index of 10=1. Plugging those number into the formula and getting a number that then will fall in the scale above. I will always round to the nearest whole number to simplify this.

Now this index is not to discourage people from doing outdoor activities. Just the opposite it’s to inform you so you can prepare and do it safely. Most people know what they can tolerate so knowing what to expect can help make a decision how what and how you do your outdoor activities this summer.