Analysis of long-term terrestrial wind speed (u) records demonstrates that interannual variability is a major component of near-surface wind dynamics in the southern Canadian Prairies (SCP). Since the early 1950s, there have been several periods when negative anomalies in regional u persisted for 8 to 13 consecutive months, with anomalies for individual months exceeding -1 m s -1. Calm conditions on the SCP usually coincided with negative u anomalies across much of western Canada, and nearly all low-wind events occurred during a 'moderate' or 'stronger' El Niño. Wind energy facilities in the SCP have been built during a period of relatively stable wind conditions, and the next El Niño may test their ability to maintain expected energy outputs. El Niño may affect u in other parts of the North American wind corridor and be useful for predicting seasonal or interannual changes in regional wind energy production.