Weatherz School: What makes the official temperature official

All it takes is a cold gust of wind or a surprising wave of sunny warmth to spark the question, “What’s the temperature?” For the most accurate answer, we have to be picky about where and how the temp is being recorded.

Car temperatures are infamously inaccurate, often on the high-end because the black-top absorbs heat from the sun. Let’s compare a thermometer outside an average house with a thermometer used for the official reading, which is sheltered by a Stevenson Screen.

The house can be in direct sunlight, but the reading we want is always shaded. Dark colors can absorb more heat, like the blacktop in our car example. Stevenson Screens are painted white to reduce heat absorption.

The house thermometer can also be influenced by radiant heat from the nearby house or concrete. A Stevenson box is in an open field at least 100 feet from any paved or concrete surface. The official reading is also at least 4 feet above the ground. All of this can contribute to error. For example, your home thermometer may read 67 degrees while the official report is 59.

However, the temperature is not the same everywhere. With elevation changes and Lake Superior, we can see big swings in temperatures between official observation sites. Sometimes, the thermometer on the side of your house might still be more accurate than the official reading.

But, if you’re on a hunt for the official temp that’s the closest to your community, look no further than the weather tab on the WDIO mobile app.