Ensemble downscaled climate dataset for Alaska and Hawaii under historical and future conditions.

While high-resolution future climate data are increasingly available for the contiguous United States, there has been limited focus on Alaska and Hawaii. Our study provides high resolution daily climate data -precipitation and temperature -at 10 km for Alaska and 1 km for Hawaii, based on 23 climate models from the Coupled Model Intercomparison Project Phase 6 and four scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). The dataset includes outputs from different bias correction techniques (seven for precipitation, six for temperature). While one method (i.e., empirical quantile mapping) generally outperforms the others, its performance can vary by climate quantity, region, or climate model, motivating our aim to provide an ensemble dataset of bias-corrected outputs. Our results show that, on average, Alaska and Hawaii are projected to become warmer (6.7 °C and 5.8 °C) and wetter (46% and 31%) by the end of the 21st century for high-emissions scenarios compared to the historical period, despite large regional variability. Our dataset aims to support climate research, mitigation and adaptation strategies, and risk assessments for Alaska and Hawaii.