# Chillin’

OK, it’s darned cold out there.  On the weekend, our outdoor thermometer sensor stopped working and we saw -.- when we looked at the thermometer.  The morning dog walk revealed that it really was cold.

As I write this, the thermometer is working again.  It says -26 but anyone who walks a Husky knows two things….

• cold is just an excuse to want to walk further
• the real story is in the wind chill factor or the feels like temperature.

According to the Weather Network, it’s just going to be a peachy dog walking day.  At least the winds are going to be weaker today.  It truly was brutal yesterday for life in the Sun Parlor.

This led me to a little investigation to answer the day’s inquiry “How do they calculate the “Feels like” value”?

But it’s not cut and dried.  Looking on the Wikipedia shows that there isn’t one simple answer.  In North America, we have the original calculation and the “new” one.  In Australia, they have an “Apparent Temperature” calculation.

Instructions and the formulae for the calculations, presumably in North American can be found here.

There are even all kinds of all kinds of applications on the web to do the calculation.  Here’s one.  Now, I can’t vouch for the validity of any of the calculations, but the reading and the formulae are interesting.  Then, I thought of the old adage – “everyone complains about the weather but nobody does anything about it”.

Well, Computer Science teachers do!

There isn’t a Computer Science teacher alive who hasn’t demonstrated or assigned a program to accept a temperature in either Fahrenheit or Celsius and had students output the conversion to the other.

So, why not construct a program to do this?

Wind chill temperature = 13.12 + 0.6215 × T – 11.37 V 0.16 + 0.3965 T V 0.16
In the above formula,
T is the temperature of air calculated in degree Fahrenheit or in degree Celsius
V is the speed of wind calculated in miles per hour or kilometers per hour

Thanks, http://www.howany.com/

Now, something like this doesn’t require a big, fancy program and compiler to work.  All I need to do is enter a Temperature and Wind Speed and do a calculation.  I had just read Alfred Thompson’s Monday “Interesting Things” blog post so I must have had Alfred on the mind.  I remembered a few years ago he told me about Microsoft’s Small Basic.  That seemed like the perfect tool.  I rebooted to run Windows and fired up the program.  Of course, there was a little bit of a learning curve to get the syntax correct (although Small Basic is really helpful as you’re writing the code).  So, I wrote the program, ran it, and got the answer that the Weather Network had generated.  How’s that for verifying that everything is working OK.  It’s somehow comforting to know that the algorithm, my coding, and the test data all converged.

Now, to convince the dog that it’s too cold to walk…

## Author: dougpete

The content of this blog is generated by whatever strikes my fancy at any given point. It might be computers, weather, political, or something else in nature. I experiment and comment a lot on things so don't take anything here too seriously; I might change my mind a day later but what you read is my thought and opinion at the time I wrote it! My personal website is at: http://www.dougpeterson.ca Follow me on Twitter: http://www.twitter.com/dougpete I'm bookmarking things at: http://www.diigo.com/user/dougpete

## 5 thoughts on “Chillin’”

1. Thanks Doug! This looks like another interesting thing I can do with my students. Especially a winter this cold.

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2. Your Husky applies the following algorithm when assessing the appropriateness of the weather for walking.

He simply removes the “you” from the equation.

Doug Walking becomes Dog Walking.

Simple.

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3. Yes, Alfred, that would be fun for the kids. Compare the various algorithms? Your followup conversation re: TouchDevelop had me thinking…this would be a great school app if you had a weather station and could feed the data to it.

Andy, that would be very easy to code!

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4. My husband and I have often talked about our memories of winter as children (well, who doesn’t 🙂 ) and we both do recall a period of time when wind chill wasn’t talked about much or reported (yes, even in the north!). The Wikipedia link seems to confirm our memories of the late 60s :). “The wind is really cold today” may have been all that we had to go on in elementary school. Is it colder in our present time? I don’t know. I still wonder if it might be best if we don’t know what it “feels like..” Your dog doesn’t… 🙂

I walked in – 30 wind chill last night… but it wasn’t that bad… I think the wind wasn’t coming off the lake though…

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