Hill, A.J. - The Albert Katz International School for Desert Studies, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, 84990, Israel

Lincoln, N.K. - Department of Tropical Plants and Soil Sciences, University of Hawai’i at Mānoa, 3190 Maile Way, St. John 102, Honolulu, HI 96822, United States

Rachmilevitch, S. - French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, 84990, Israel

Shelef, O. - Department of Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, 7505101, Israel

Dew formation is an essential component of the water balance in dry ecosystems, but measuring dew is challenging due, in part, to its dependency on the surface on which it forms. We detail the use of a modified Hiltner dew balance to illustrate how more accurate measurements of dewfall may be obtained. Using a modified Hiltner dew balance, we measured dewfall in the Negev Desert continuously for 3 years (2013–2015). Data analyses examined the relationship between dew formation, rain events and other environmental parameters in order to re-evaluate the importance of dew in the water budget. In line with previous research, our findings demonstrate that dewfall is a substantial and stable input of water in the Negev desert, providing inputs in the dry summer and the wet winter. Our results show that while dewfall was larger and more prevalent in proximity to rain events, a notable portion of dewfall took place on days distant from any rain event. The Hiltner dew balance modifications proved to be reliable and increased the efficacy of measuring the quantity and timing of dew formation. This study demonstrates the importance of integrating dewfall data into decision-making models for dryland ecosystems and agriculture, as well as into climate models.