ROCHESTER, N.Y. — It is highly unusual to get major changes in the temperature this time of the year. But this season has been a little different. Recently Rochester had temperatures only in the 50s, but there is a major change set to happen in the overall weather pattern. This will take place early next week with the jet stream shifting on Monday, Tuesday, and Wednesday — and that will drive a tremendous amount of heat and humidity back into Western New York.

On these hot days it can be fun to measure how high the temperature will get in a heat wave. However, quite often there can be a significant difference between the temperature at your house or in your car compared to the Rochester airport. Why the disparity?

There are a lot of ingredients going into that temperature, but that disparity can also be due to how and where we place that thermometer. The Rochester airport uses an instrument shelter and, as the name suggests, it is always shaded from the sunshine and precipitation. The thermometer at your house could be getting a little bit of direct sunshine, and that creates an artificially reading. The airport shelter is painted white and is vented. That will also reduce the amount of heat absorption. The thermometer at your house could be near dark colors that can absorb more heat. In addition, the airport measures the temperature four feet off the ground and is located over an open field of field of grass. In contrast, your temperature sensor might be located over concrete or asphalt. That is not an ideal setting for accuracy.

I always remember “back in the day” watching a television baseball game in Kansas City, Mo., with mid-summer heat. The television network was claiming it was 120 degrees on the field. They showed one of these thermometers sitting on the Astroturf measuring the temperature directly in the sunshine. That is an extreme example of an artificially measurement of the temperature.

Keep that in mind: How you shelter your thermometer is all-important to achieving true accuracy.