Temperature versus elevation relationships for Puerto Rico 1,2 Megh R. Goyal, Eladio A. González and Carmela Chao de Báez 3 ABSTRACT Relationships among mean daily maximum-, mean daily minimum-, mean daily average-, absolute highest-, absolute lowest temperature (°C) versus elevation (m) were determined for January through December for Puerto Rico. These relationships were found to be linear, Y — A + BX. The coefficient of correlation varied from —0.43 to —0.96. Examples are pre- sented to estimate potential evapofranspiration (PET) and to develop PET model as a function of incident solar radiation and elevation. RESUMEN Relación entre temperatura y elevación en Puerto Rico La relación entre las temperaturas (°C) media diaria, máxima diaria, mínima diaria, más alta y más baja para cada mes contra la elevación (m) se determinaron de enero a diciembre para Puerto Rico. Se encontró que estas relaciones son lineales. El coeficiente de correlación varió de -0.43 a -0.96. INTRODUCTION Water consumptive use by crops in any particular location is probably affected more by temperature, which for long-time periods is a good measure of solar radiation, than any other factor. Abnormally low tem- peratures may retard plant growth and unusually high temperatures may produce dormancy. Temperature is one of the most dynamic proper- ties of weather and is subject to daily and seasonal changes. Irrigation planning can be delayed or underestimated if temperature data for vari- ous locations in a particular locality is not available.' 1 The objective of this study was to establish relationships among monthly temperature (°C) and elevation (m) for Puerto Rico with avail- 1 Manuscript submitted to Editorial Board 19 March 1987. 2 This study was conducted under C-411, "Bioclimate of Puerto Rico" and CBAG-PR-23 "Irrigation Estimations in Puerto Rico." The authors thank George H. Hargreaves for his valuable guidance. 'Associate Agricultural Engineer, Research Assistant (Agronomy), and Associate Statistician, Agricultural Experiment Station, University of Puerto Rico, Mayagüez Cam- pus, Río Piedras, P. R. 4 Hargreaves, G. H. and Z. A. Samani, 1986. Simplified irrigation scheduling and crop selection for EI Salvador. Utah State University, Logan-Utah. Personal communication - November 5. 449