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In semiarid rangelands, initial seedling establishment is a key, weather-sensitive demographic bottleneck in restoration of perennials such as sagebrush. We assessed differences in physiological responses of big sagebrush (Artemisia tridentata) to weather among eleven seed sources that varied in subspecies, cytotype, and climate-of-origin following outplanting. Preliminary results showed that seasonal timing of mortality was associated more with minimum temperatures rather than water deficit. There were also large differences in physiological, freezing-temperature thresholds among subspecies and cytotypes, particularly in the temperature causing cellular ice formation than for the temperature causing 50% loss of photosynthetic function. In contrast, physiological responses to water did not correspond to survival patterns. Our findings on the importance of minimum temperature thresholds for restoration plantings in these water-limited rangelands are corroborated by a related study that found that matching minimum temperatures of seed source and seeding sites enhanced restoration success in 24 historic, large-scale seedings done from 1987-2010 on wildfire areas. Sagebrush seeds were transported from high to low elevations in these seedings, ie. cool/wet-adapted seed sources were imported into warmer and drier burned areas. Daymet weather simulations over the >100,000 acres and decades of these seedings revealed that much colder and wetter weather, particularly 3-4 years after burning and seeding, led to greater establishment. These findings lead to the hypothesis that introduction of cool/wet-adapted seeds for restoration or rehabilitation of burned areas has caused sagebrush establishment to favor cool/wet weather, even though low-temperature thresholds are a key limitation to seedling survival. Climate and particularly weather thresholds are clearly important factors for post-fire vegetation establishment. Our study used statistical methods and weather data to reveal weather thresholds useful for modeling, and can be adopted to evaluate the many other seedings and plantings that are increasingly invested in to restore sagebrush-steppe rangelands.