From July 17th to October 15th of 2019, field testing of irrigation controllers was undertaken to verify procedures and calculations in support of finalizing alternate protocol #2 of the proposed ASABE X627 testing standard for weather-based irrigation controllers. Three different weather stations in northeastern Colorado were utilized for reference. Ten different make/model of controllers were included, with replicates of each, for a total of 24 individual controllers. All of the controllers included in the field testing had previously been awarded the Water Sense certification label by the Environmental Protection Agency. ASABE X627 has since been finalized as ANSI/ASABE S627 DEC2020, Weather-Based Landscape Irrigation Control Systems standard. However, EPA Water Sense is not expected to adopt alternate protocol #2. Of the ten make/model of controllers, four performed well. Three were wi-fi based and utilized weather data available via the internet. The fourth successfully utilized onsite wireless weather sensors. An additional wi-fi based controller performed fairly well, however two of its replicates did not provide useable data. Five of the ten make/model of controllers performed poorly. Three utilized onsite wireless weather sensors with suspected intermittent communications. A fourth make/model (wi-fi based) apparently would not retain every input parameter entered into its programming. The fifth make/model of controller relied upon a weather server which was periodically offline (the controller product was acquired by a different company and support services were intermittent during the transition). An online presentation of results from the field testing of alternate protocol #2 was hosted by the IIC on November 10th. A recording of the presentation is currently available for viewing on the IIC’s YouTube channel. Test results for individual controllers have been shared with the corresponding manufacturer. Each has been invited to contact IIC Assistant Director A.J. Brown  if they have interest in further controller testing using alternate protocol #2.