Environmental Monitoring with Arduino

Getting Usable Measurements

There are a lot of variables involved in getting accurate temperature readings. Are you measuring the temperature indoors or outdoors? In a closed stuffy room, or in one with lots of ventilation? Over a black asphalt driveway or over relatively cool white concrete, in full sunlight or in the shade?

These widely varied conditions can result in wildly different readings, even if they’re taken at the exact same moment.

Weather professionals have developed a method to ensure they’re all measuring temperature the same way across multiple outdoor locations. They place a thermometer in a Cotton Region Shelter (CRS), a white-painted pinewood box with a solid top, slatted sides, and a slotted bottom, and place it five to six feet off the ground.

The CRS protects the thermometer from sun, rain, snow, and more—from everything except air temperature.

You don’t need a CRS in order to use this gadget (though building one would be an awfully cool project—here are some sample specs from the National Weather Service). But we do recommend that you find a way to create consistent conditions when you use it.

Indoors, this should be fairly easy. Find a place to keep the gadget that emulates the advantages of a CRS: out of direct sunlight, away from heating or cooling vents, several feet off the ground.

Outdoors, however, you’re going to need something more like a CRS, something that is waterproof but allows for circulation of air around the sensor.

Weather and Climate: What’s the ...