The pilot listened to the recorded weather information then took off on the airport’s only paved runway with a direct crosswind of about 5 kts. He described that during the initial climb, the airplane encountered either a downdraft or increasing wind over trees next to the runway that resulted in the airplane rolling left. The pilot attempted to counteract the roll; however, the airplane settled off the sloped left side of the runway, impacted a berm, bounced up, and came to rest on the taxiway. The left wing was substantially damaged. The pilot reported that there were no preimpact mechanical malfunctions or failures of the airplane that would have precluded normal operation. Postaccident communication with the Federal Aviation Administration revealed that the airport manager’s weather reporting system included gusting wind that was not reported by the automated weather system.