utf8 dataset dataset 2025-08-11 ISO 19139 Geographic Information - Metadata - Implementation Specification 2007 originator Heat Zones map the distribution of potential heat stress for plants and animals, including humans. Heat zones, defined as the number of days per year with maximum daily temperature >= 30 °C (86 °F). Daily maximum temperature values >= 30 °C during the period 1980 - 2009 were tallied annually and are reported as the average annual number of days during a 30-year period. Heat Zones are used to capture a gradient of conditions. While temperatures exceeding 30 C do not represent a species specific physiological threshold, it is noted that these temperatures are above a general optimal threshold for photosynthesis for plants (Rennenberg et al. 2006). Daily temperature values downscaled by Maurer et al. (2007) were obtained and processed to create this data layer. Daily temperatures surpassing the 30 C threshold were tallied and summed for each year and reported as the mean number of days, per year, over the 30-year period of 1980-2009. Simulated historical values for the period 1980-2005 and future projections (2006-2099) from the Community Climate System Model (CCSM4) (Gent et al. 2011), a general circulation model under a representative concentration pathway 4.5 (Moss et al. 2008). These data were statistically downscaled via asynchronous regional regression modeling to a resolution of 1/8th degree (~13.875 x 13.875 km) (Maurer et al. 2007). Cathey, H.M. 1997. Announcing the AHS plant heat-zone map. Amer. Gardener 76(5):30-37 Gent, P.R., Danabasoglu, G., Donner, L.J., Holland, M.M., Hunke, E.C., Jayne, S.R., Lawrence, D.M., Neale, R.B., Rasch, P.J., Vertenstein, M., Worley, P.H., Yang, Z., Zhang, M. 2011. The Community Climate System Model Version 4. Journal of Climate 24(19): 4973-4991. Maurer, E. P., L. Brekke, T. Pruitt, and P. B. Duffy (2007), 'Fine-resolution climate projections enhance regional climate change impact studies', Eos Trans. AGU, 88(47), 504. Moss, R. H., M. Babiker, S. Brinkman, E. Calvo, T. Carter, J. Edmonds, I. Elgizouli, S. Emori, L. Erda,. et al. 2008. Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts, and Response Strategies. Intergovernmental Panel on Climate Change, Geneva, 132 pp. USDA - GEO; USDA - USFS – GTAC Climate Temperature Heat Zones Historical CONUS US Forest Service USFS IIPP Interdepartmental Imagery Publication Platform Enterprise Data Warehouse EDW These data were created using funding from the U.S. Government and can be used without additional permissions or fees. If you use these data in a publication, presentation, or other research product please use the citation below when citing the data product:Matthews, Stephen N.; Iverson, Louis R.; Peters, Matthew P.; and Prasad A. 2019. Climate Change Pressures: Plant Hardiness Zones, Heat Zones, Growing Degree Days, and Cumulative Drought Severity. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2019-0001Please note: This dataset is the product of modeling, and as such carries an inherent degree of error and uncertainty. Users must read and fully comprehend the metadata and other available documentation prior to data use. Users should acknowledge the Originator when using this dataset as a source. Users should share data products developed using the source dataset with the Originator. No warranty is made by the Northern Research Station (NRS) or USDA Forest Service as to the accuracy, reliability, or completeness of these data for individual use or aggregate use with other data, or for purposes not intended by the USDA Forest Service. These products are intended to support regional strategic planning. 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