MORE VARIABLE AND EXTREME WEATHER PATTERNS, SUCH AS DROUGHTS RIVALING THAT OF THE DUSTBOWL, ARE A PROMINENT FEATURE OF CLIMATE CHANGE PROJECTIONS AND POSE A FUNDAMENTAL CHALLENGE TO RAIN-FED RANGELAND PRODUCTION SYSTEMS. RANCHERS HAVE THE POTENTIAL TO MITIGATE THE UNCERTAINTY POSED BY INCREASING CLIMATIC VARIABILITY THROUGH PRO-ACTIVE DECISION MAKING THAT CAN HAVE PROFOUND ECONOMIC IMPLICATIONS, BUT THIS RELIES UPON KNOWLEDGE OF WHEN TO IMPLEMENT SUCH DECISIONS. AND WHILE A GROWING BODY OF RESEARCH HAS SHOWN THAT FORAGE PRODUCTION IS SENSITIVE TO WEATHER VARIATION DURING RELATIVELY NARROW PERIODS DURING THE GROWING SEASON, WE LACK AN UNDERSTANDING OF HOW THIS TIMING OF FORAGE SENSITIVITY TO WEATHER VARIES AT THE SPATIAL SCALES IN WHICH DECISION MAKING OCCURS, FROM THE LANDSCAPE, COUNTY, AND STATE ALL THE WAY TO THE SCALE OF THE ECOREGION. THE GOAL OF THIS PROPOSAL IS TO IMPROVE OUR UNDERSTANDING OF RANGELAND RESPONSES TO WEATHER VARIABILITY BY FOCUSING ONWHENPRECIPITATION MOST AFFECTSFORAGE PRODUCTION AMONG DIFFERENT RANGES IN THE WESTERN UNITED STATES. UNDERSTANDING THIS TIMING WILL PROVIDE ABOUT CRITICAL DECISION DATES: THE DATES DURING THE GROWING SEASON BY WHICH RANCHERS SHOULD INITIATE DROUGHT MITGATION STRATEGIES SHOULD BE INITATED IF DROUGHT CONDITIONS HAVE EMERGED.