Six Colors
Six Colors

by Jason Snell & Dan Moren

Exercise Your Rights

Americans, here's everything you need to vote.

By Dan Moren

Automate This: How hot does it feel?

It’s hot.

How hot is it, Dan?

So hot that apparently I’ve taken to creating temperature-related shortcuts?

It started out with a relatively simple idea: I wanted to know if it was cooler inside or outside of my house, to dictate whether or not we should open the windows. Fortunately, last fall I purchased an Eve Degree, a little HomeKit-compatible sensor that can measure temperature and humidity. It sits on the dresser in my bedroom so I can glance over and quickly see the current temperature on its display, or look it up in the Home app.1

So, I put together a little shortcut that gets the current outdoor temperature and compares it, then tells me where it’s warmer.

Of course, that wasn’t enough. I quickly realized I have two possible sources in my house, as my office has a Philips Hue Motion sensor that can also measure temperature. So, I now have the temperature comparison shortcut average the two temperatures (which are rarely more than a degree or two apart), just so I can get a better sense of indoor temperature.

All well and good. But we all know—especially those of us that live in moister climates like New England—that what the temperature is and what it feels like are two different things. And while most weather apps can provide a “feels like” temperature (also known as the heat index), my indoor temperature sensors don’t have that information.

Or do they? How is the heat index calculated anyway? Well, the fine folks at the U.S.’s National Weather Service not only provide a handy web-based heat index calculator but are also thoughtful enough to publish the mathematical formula behind it. All the calculation requires is the temperature and the relative humidity, both of which the Eve Degree can measure, so all I have to do is plug those values into the formula.

Well, what’s a computer good at if not mathematical formulas? So I set out to build my own shortcut to calculate feels like temperature. In a bit of serendipity, one of the actions I needed—Calculate Expression, which lets you just throw a bunch of math into an action—was just added in iOS 14, so I composed the shortcut in the beta. It took a little work to figure out exactly how to convert the notation from the formula into a shortcut-friendly version, but after a bit of trial and error, I figured it out.

And so, voila! Pass this shortcut temperature (in Fahrenheit) and humidity2 and it’ll pass you back the “feels like” temperature. (The version there requires iOS 14, as mentioned, though some third-party apps, such as ToolBox Pro, may offer actions that can handle the work of the Calculate Expression action.)

For my purposes, I’ve wrapped it in a second shortcut that retrieves the temperature and humidity from my home sensors and formats the output to compare it to the outside temperature, but you can adapt it for whatever purposes you want.

Now, if you don’t mind, it feels very hot in here, so I’m going to…uhh…consults shortcut…stay inside, I guess.


  1. See? Jason’s not the only one who can create weather-related automations. 
  2. In a dictionary, for the Shortcuts-conversant readers among us. 

[Dan Moren is the official Dan of Six Colors. You can find him on Twitter at @dmoren or reach him by email at dan@sixcolors.com. His latest novel, The Aleph Extraction, is out now and available in fine book stores everywhere, so be sure to pick up a copy.]

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