Collecting Weather Data


The Mesonet weather stations collect 18 different parameters of weather data every minute, every day of the week, 365 days per year. The data from the Mesonet are given a time stamp (so you know when they were collected) in Central Standard Time (CST). So when you look at the data on this website during daylight savings time, you have to add 1 hour to the times listed in tables or charts to obtain the actual Daylight Savings Time (CDT). The text below describes what weather parameters are collected and why they are important.

Air temperature

Temperature controls how comfortable we feel and whether we can wear shorts or need to put on a jacket when we go outside. It also determines whether we run our air conditioning or heater and this is important to power companies. On extremely hot or unusually cold days, power companies need to plan for increased demand on their resources. Temperature also affects the comfort of wildlife and our ecosystems which are important to our seafood and tourism industries. Agriculture is also affected by temperature, for example strong freezes can harm the citrus growing industry.

The Mesonet stations measure temperature at 4 different heights (1.5, 2, 9.5 and 10m) this is done for two important reasons. Firstly, the thermometer pairs placed 50 cm apart (i.e. those at 1.5 and 2 m and the pair at 9.5 and 10m) serve as backups to one another. If one thermometer fails due to extreme weather or if the sensor malfunctions, there is a second sensor available. A second reason for measuring temperature at different levels is to obtain information about atmospheric stability. During the day, the sun warms the surface and the air temperature decreases with height. Since warm air rises, this means the surface air wants to continually move upward while cooler air sinks down. This causes turbulence, or mixing of the atmosphere and we call the air unstable. At night the reverse happens and the air temperature warms as you go up in the air, this is called a stable. air layer. Mixing does not occur and pollutants, pollen, and dust particles remain close to the surface. This can cause problems with air quality and allergies.

Surface temperature

Surface temperature is important to farmers, if the soil is too hot or too cold certain crops can or cannot grow. Surface temperature also controls the temperature of the air immediately above. During clear days, the sun warms the surface which in turns warms the air it is in contact with. Since warm air wants to rise, this can lead to cloud formation, and thunderstorms if the air is moist enough.

Relative Humidity

Relative Humidity is a measure of the amount of moisture, or water vapor, that is present in the air. Like temperature, it also affects our comfort. Extremely humid and hot days will be issued a heat index that is much warmer than the actual temperature. The extra humidity in the air makes it feel much warmer than it actually is. Measuring humidity helps forecasters determine whether there is a chance of thunderstorms on hot days or when a front comes through. Humidity is also important to certain industries. For example, for concrete to set the humidity cannot be too low or too high.

The Mesonet stations measure humidity at 2 different levels (2 and 10m), this is done mainly for sensor redundancy, so if one sensor breaks, the other will still be available.

Wind speed and direction

Wind can cause a lot of damage as we know from tropical storms, hurricanes, tornadoes, and even severe thunderstorms. Records of wind speed are useful for litigation purposes but also for research of severe weather events and hurricanes and to determine if wind energy is viable in our region. Wind direction gives us information about where the wind comes from, and thus what kind of air is entering our region. During the summer the wind in our area blows mainly from the hot, humid Gulf, explaining our warm, moist summers. In winter the wind often blows from the north bringing cold, dry air from colder regions to our north into our area. Knowledge of wind speed and direction is important during chemical spills because emergency managers can use the wind information to predict where the plume of chemicals is going. This way, residents in its path can be warned to evacuate or stay indoors.

Again wind speed and direction are measured at two different levels (2 and 10m). This allows the study of turbulence in the atmosphere which in turn is important for atmospheric mixing and air quality.

Vertical wind speed

This parameter gives information about whether the wind is blowing up (positive vertical wind speed values) or down (negative values). The Mesonet stations measure vertical wind speed at one height only: 10m. This parameter provides information about turbulence which is important for atmospheric mixing and air quality. Large vertical wind speed values, indicate strong turbulence.

Solar radiation

The Mesonet measures solar radiation in the visible range of the total spectrum of electromagnetic radiation emitted by the sun. The total spectrum also includes infra-red (heat) and ultra-violet radiation. Light energy is important to plants for growing (using photosynthesis) and can be turned into energy using solar panels. The amount of radiation we receive at the top of the atmosphere can be calculated because we know when the sun rises and sets and we know the sun angle (height of the sun in the sky). However, clouds and particles and dust suspended in the air can change the amount of radiation we receive at the surface. Clouds, moisture and dust can filter out and reduce radiation, but in some cases it is reflected back to the surface increasing the total amount of radiation received.

The Mesonet stations measure two types of visible radiation; the differences are in the wavelengths measured. Total solar radiation is measured in the 400-1100 nm range, while photosynthetically active radiation occurs in the narrower 400-700 nm range. The latter is of specific interest to farmers and growers because it determines how much energy is available to plants and trees for photosynthesis (turning carbon dioxide into sugar using light energy). Solar radiation is also a potential renewable energy source that may work well in our relatively sunny region. Solar radiation data measured by the Mesonet allows researchers to explore such opportunities.


Rainfall is another parameter that affects our comfort and determines what we should wear. But it has much further-reaching consequences than our personal comfort. Rainfall is important to farmers; extreme droughts or excessive rainfall will destroy crop production. Rainfall causes run-off and can wash pollution, litter, and harmful substances into our adjacent larger water bodies such as rivers, bays and ultimately the Gulf. This negatively impacts fish and other wildlife and, hence, our seafood and tourism industries. Intense rainfall can produce flooding, while lack of rainfall can produce drought and shortage of water supplies in reservoirs.

Each Mesonet station has 2 rain gauges for backup purposes. Rain gauges often become clogged up with debris. Insects and other small animals frequently build nests in the rain gauge funnels. This causes the gauges to malfunction. Having a backup gauge reduces the chances of missing rainfall recordings.

Atmospheric pressure

Two identical pressure sensors record atmospheric pressure at the Mesonet stations. Two sensors are used for redundancy; if one breaks or drifts out of calibration, the other barometer will still be available. Pressure does not directly impact life or human comfort, but it does provide meteorologists with valuable information about approaching weather systems. Most weather makers (fronts, tropical storms, hurricanes, mid-latitude storms) are low pressure systems. As such a system moves in, the pressure drops, indicating bad weather is imminent. High pressure, on the other hand, usually indicates calm and sunny conditions.