A Grower's Guide on Selection and Use of Weather Stations for Improving Crop and Irrigation Management Decisions

Data is most reliable within a 60-mile radius for largescale weather patterns and within 6 miles for local applications, such as precision farming, where farmers use weather data to improve irrigation (World Meteorological Organization, 2008). Relative humidity (RH, %) data were recorded directly in a grower’s field located in Gila Bend, Arizona, using a Li710 device. The data were compared to values obtained from the nearest AZMet weather stations, Paloma at 15 miles, Buckeye at 27 miles, and Harquahala at 41 miles from the field site. Figure 2 shows how the humidity changed during the day and night over one week, February 12-19, 2025. This comparison helps highlight differences that can happen between actual field conditions and weather station data. This example highlights how the distance between a field and a weather station can influence how representative weather data from another location may or may not be for a local field. Since relative humidity is one of several parameters used to estimate reference evapotranspiration (ETo), differences caused by measurement distance, or other factors such as whether the other locations are in production or have been recently irrigated, may impact local irrigation decisions. While additional data over a longer period is needed to validate these observations, the preliminary findings suggest that having on-farm weather stations could improve the representativeness of ETo calculations for site-specific management.

There are many types of weather instruments and sensors available for weather stations, but the primary consideration for growers is to determine which environmental conditions are most important to monitor for their specific crops or farming needs, and the quality of the data. Based on our own experience and typical company descriptions, we have defined three categories of weather stations, although the division of categories is debatable: Basic, Advanced Research Grade, and Smart. Both the Basic and Advanced Research Grade weather stations can be Smart, where Smart refers to connectivity to the cloud, processing of data in the cloud, and real-time evaluation of such parameters as reference evapotranspiration. Basic weather stations typically have fewer and less expensive sensors than Advanced Research Grade weather stations. They typically include wind speed meters (anemometers), air temperature sensors (thermistors), humidity sensors (hygrometers), air pressure gauges (barometers), rain gauges, and sunlight sensors (pyranometers). Advanced Research Grade crop monitoring systems include higher quality weather sensors as well as a range of sensors that focus on crop growth, soil moisture, and irrigation status. In addition to weather stations, satellite-based and model systems such as OpenET (https://etdata.org/) and Meteoblue (https://www.meteoblue.com/) provide useful data for crop and irrigation management (Attalah et al., 2024). Evaluation and prioritization of data types and required data quality guides the selection of weather station platforms, satellite systems, and other sensors.

Table 1 illustrates the levels of weather stations, Basic, Advanced Research-grade, and Smart, highlighting their typical features, advantages, and potential drawbacks. Basic Weather Stations (BWS) monitor basic parameters such as air temperature, atmospheric pressure, humidity, wind speed and direction, solar radiation, and precipitation. They are cost-effective and user-friendly, but the accuracy of their sensors may be lower. Advanced Research Grade Weather Stations (ARWS) include higher quality and additional sensors, and calculate crop parameters, such as reference ET. The ARWS generally incorporate high-precision sensors for superior data accuracy and detailed analysis. But they have higher capital, installation, maintenance, and annual calibration costs. These stations are optimal for scientific research but are expensive, complex, and generate vast amounts of data that may exceed the needs of typical agricultural operations. Nevertheless, they provide superior data, which may be preferable for some growers.

Smart Weather Stations (SWS) connect to the cloud and provide real-time data accessibility on the phone or other smart devices and provide data processing and estimates of parameters such as reference evapotranspiration. Companies generally charge an additional fee for this service. The extra charge for the SWS may pay off overtime through reduced maintenance needs, less manual interference and better long-term reliability.

The accuracy and reliability of weather data are essential for making informed farming decisions. Therefore, knowing how and where to install a weather station is a vital key to achieving this goal. The following are some important steps to consider:

• Location: A weather station should be located in an open space away from obstacles such as buildings, fences, or trees, and where it can be easily accessible. A distance greater than 10 times the height of the nearby obstacle is usually recommended (Onset, 2010). Since they are intended to support farming, a long-term reserved space should be considered.
• Ground: Leveled ground is required for some instruments, such as rain gauges, and pyranometers (Photosynthetic Active Radiation sensors). Distance above ground is also important. For example, a height range of 1.3 to 2.0 m (4.1 to 6.6 ft) is suitable for thermometers and hygrometers, while rain gauges are typically installed at a standard height of 1.0 m (3.3 ft) above the ground. Anemometers are generally positioned between 2.0 m and 3.0 m (6.6 to 9.8 ft) above the ground (https://www.weather.gov).
• Weatherproof enclosure: Weather instruments such as thermometers and hygrometers should be protected from direct sunlight while mounted in a place with free airflow.
• Security: Weather stations should be easily accessible for data collection, inspection, and regular maintenance. Unattended stations require a secure area to avoid the risk of natural damage or vandalism.
• Maintenance: ARWS are recalibrated, with AZMet doing so four times per year (https://azmet.arizona. edu/about/general-operations).

As described previously, weather stations come in different shapes and sizes which make their cost spread over a wide range. Moreover, the cost of the same weather station or sensors may vary from one company to another, depending on the technology and service plan they offer. The National Weather Service (NWS) has published an extensive list of weather companies (https://www. weather.gov/enterprise/meteorological-instruments-6a), referring to their websites, the weather aspect addressed, and the services they provide. The present publication is an attempt to highlight the main criteria a prospective user would consider in purchasing relevant weather sensors, a complete set of sensors, or an entire weather station based on technology, connectivity, and cost information currently published. The specificities of each product are normally detailed in the companies’ websites in brochures, manuals, and catalogs. The published products are mostly categorized as remote monitoring systems, data loggers, sensors, and service plans. Overall, an informed decision when purchasing a weather station or weather sensors should consider relevant and effective equipment while maintaining an affordable cost range. For illustration with relevance to farming management, we included the cost range of some weather equipment that can be integrated in WS, along with a short description and types of weather variables that each instrument can measure, as currently published by different companies (Tables 2-5).

The examples presented in Tables 2-5 show how wide the current cost range is from one company to another, even for the same type of instruments or services. The displayed prices ranged from $188 to $20,800 for weather stations (monitoring systems), $69 to $2,290 for data loggers, $47 to $1,800 for sensors, and $25 to $449 for service plans. Although the cost of some items might seem high, it should not be the only selection parameter to consider in choosing a WS or customizing an existing system. In some cases, the trade-off between usage convenience and cost affordability might be inevitable. For instance, cabled sensors are usually cheaper but cumbersome, whereas the wireless ones are convenient but require a reliable transmitting system, which makes them expensive. Moreover, the same parameter, such as temperature (T) or humidity (H), can be measured either with an inexpensive instrument ($31, Table 4) or an expensive sensor ($784, Table 4), both of which are offered with different packages. The type of weather station can also influence the cost, with research-grade stations costing more compared to basic stations. While price variability should be considered, data accuracy, acquisition time, and relevance should be the decisive criteria to fulfill the requirements of an effective weather station, especially in the farming sector.

Table 1. Instruments and their functions for the different types of weather stations.

Table 2. Monitoring systems’ type, description, and prices from different sources. 

Table 3. Data loggers’ type, description, and prices from different sources.

Table 4. Weather sensors’ type, description, and prices from different sources. 

Table 5. Service plan type, description, and prices. 

Successful agricultural operations rely on accurate and timely weather data that is representative of local field conditions to optimize planning and management while minimizing risks. AZMet weather stations have been installed throughout Arizona to support farm management. However, for the many farms in Arizona located far away from an AZMet station, data from the nearest AZMet station may not be representative. In these situations, on-site weather station data could ensure a more reliable data source based on the actual weather conditions on the farm. Local weather data are particularly important for assessing the irrigation application amounts needed to replace actual crop evapotranspiration using reference ETo methods. Spatial variations of ETo and precipitation are especially wide during the monsoon and winter seasons, which makes having local data even more important. Thus, a weather station for an Arizona grower should include, at a minimum, sensors needed to calculate ETo, including an air temperature sensor, a relative humidity sensor, a solar radiation sensor [pyranometer], and a wind speed sensor [anemometer]. To help manage field operations, other sensors would be required too, such as rain gauge, leaf wetness, soil moisture, and soil temperature sensors. These support decisions on irrigation, pest control, disease prevention, and overall crop health.

A wide range of weather stations is available on the market, but an effective system should include all the essential instruments necessary to support the grower’s goals. Choosing the right weather station is a critical decision that involves selecting appropriate sensors, ensuring proper installation, maintenance, and calibration, and considering long-term durability. A fully equipped weather station can assist in necessary farming activities such as irrigation scheduling, pest and disease management, and climate deviation strategies.

While the cost of individual instruments may seem high, assessing the value of a complete system rather than isolated components is essential. Cost is an important factor in decision-making, but it should not be the sole criterion, as the accuracy, reliability, and overall functionality of the system are equally crucial for achieving optimal agricultural outcomes.

This publication is intended to provide an objective overview of the use of weather stations in farming and does not promote or endorse any specific brand, product, or trademark. References to product names, trademarks, or companies are included solely for informational purposes.

Allen, R.G., Pereira, L.S., Raes, D., Smith, M., 1998. Crop evapotranspiration-Guidelines for computing crop water requirements-FAO Irrigation and drainage paper 56. FAO, Rome, Italy.

Attalah, S., Elsadek, E.A., Waller, P., Hunsaker, D., Thorp, K., Bautista, E., Williams, C., Wall, G., Orr, E., Elshikha, D.E., 2024. Evaluating the Performance of OpenET Models for Alfalfa in Arizona, in: 2024 Anaheim, California July 28-31, 2024, ASABE Paper No. 2400041. American Society of Agricultural and Biological Engineers, St. Joseph, MI, p. 1. https://doi.org/10.13031/aim.202400041 

Bayer, A., van Iersel, M., Chappell, M., 2023. What is a weather station, and can it benefit ornamental growers? [WWW Document]. URL https://secure.caes.uga.edu/extension/publications/files/pdf/B1475_4.PDF (accessed 4.17.25).

Brown, P., 2000. Basics of Evaporation and Evapotranspiration [WWW Document]. URL http://hdl.handle.net/10150/146968 

Brown, P.W., 2013. Heat units [WWW Document]. URL http://hdl.handle.net/10150/299154 (accessed 4.17.25).

Helms, D., 2005. Citizen Weather Observer Program (CWOP). Weather Station Siting, Performance, and Data Quality Guide [WWW Document]. URL https://www.weather.gov/media/epz/mesonet/CWOPOfficialGuide.pdf (accessed 4.17.25).

Onset (2010). Deploying Weather Stations: A Best Practices Guide. https://www.onsetcomp.com/resources/whitepapers/deploying-weather-stations-best-practices-guide  

Prentice, I.C., Cramer, W., Harrison, S.P., Leemans, R., Monserud, R.A., Solomon, A.M., 1992. Special paper: a global biome model based on plant physiology and dominance, soil properties and climate. J. Biogeogr. 117– 134. https://doi.org/10.2307/2845499 

World Meteorological Organization, 2008. Guide to Meteorological Instruments and Methods of Observation. ISBN 978-92-63-100085. 7th edition. https://www.weather.gov/media/epz/mesonet/CWOP-WMO8.pdf (access 4.17.25).