Observing and recording weather information at home can be an interesting and fun hobby. Some people even supply their weather readings to local TV stations and the National Weather Service.
Home weather stations can be as simple as a thermometer or as complex as the electronic marvel I use that provides current, maximum and minimum temperatures, wind speed and direction, peak gusts, wind chill and heat index, number of heating and cooling days, relative humidity, dew point, barometric pressure, precipitation, and many other things. The data is stored electronically and downloaded automatically into my computer. Then my weather program plots a variety of charts and graphs as well as monthly and annual summaries. The daily weather data and monthly summaries printed in the Nacogdoches Daily Sentinel are from my station.
Most people put their weather instruments where they’re easy to see, but that’s usually not the best location. For example, thermometers mounted near a window pick up heat leaking from the house and give abnormally high readings. Ideally, your thermometer should be mounted in a shaded, grassy location about five feet off the ground, away from pavement where air can circulate freely around. Be particularly careful that it’s never in the sun. When sunlight hits a thermometer, it heats the instrument so you are not reading actual air temperature.
At the Nacogdoches airport, where KTRE-TV and local pilots get their readings, pavement, parking lots, runways and buildings surround the sensors, causing artificially warm readings. The airport’s wind direction and speed sensors are close to their roof where eddies and currents can cause incorrect readings.
Once my rain gauge showed a total of just over 4 inches, but the station at Stephen F. Austin State University indicated a little over an inch, even though the two locations are only about 3 miles apart. They were both right. Small storm cells had been moving through the area, each one in a different location. So, don’t worry if your rainfall reading is different than what the TV meteorologist reports. It can be pouring at your neighbor’s house across the street and just drizzling at yours.
There are many kinds of temperature sensors available nowadays, including low-cost digital ones that will give current temperature and also keep track of the highs and lows. Some even have a remote temperature sensor combined with a radio transmitter that will send the information to a readout inside your house.
The amount of moisture in the air is called relative humidity and is the percentage of water vapor the air can hold at the current temperature. It’s measured by using an electronic sensor or a hygrometer using stretched hairs that lengthen and shorten with changes in humidity. There are also wet bulb/dry bulb hygrometers. Using a chart, the difference between the wet bulb and dry bulb temperatures gives the humidity. Electronic humidity sensors that read remotely are also available. Whatever you use, the sensor must be outdoors or else you’re just reading the humidity of the air inside the house.
Your rain gauge should be mounted one to five feet above the ground and as far from trees or buildings as possible, so that wind currents won’t cause incorrect readings. I use a digital gauge that reads remotely in the house and as a backup, a simple plastic one that is checked visually. The plastic gauge must be emptied regularly, but the digital one has a small tipping bucket inside that flips over every time 0.01” of rain accumulates, dumping the water out.
Barometers can be located almost anywhere inside your house. Air pressure indoors is the always the same as outdoors. Houses are not really air-tight. If they were and the air pressure was different outside and inside your house, the walls would either pop out or collapse. Be sure to initially set your barometer to your correct elevation above sea level of your home, or use a reading from a local weather data source. For your purposes, that will be accurate enough.
Wind instruments should be located 15-20 feet above the ground and at least three times farther away than the height of any nearby trees or buildings. For most home stations that’s unrealistic, so the anemometer and wind vane are often mounted on the crest of the roof or on a TV antenna mast. Just try to mount them as high as possible to avoid deviations caused by air rushing around and over the building.
You can’t completely escape the weather and its influences. Like compound interest and taxes, it’s always with us and sometimes it’s just as irritating. But, it’s also a very interesting part of our environment and I encourage you to watch it more closely.
Dr. Risk is a professor emeritus in the College of Forestry and Agriculture at Stephen F. Austin State University in Nacogdoches, Texas. Content © Paul H. Risk, Ph.D. All rights reserved, except where otherwise noted. Click firstname.lastname@example.org to send questions, comments, or request permission for use.