On my last several flights in the A350-900ULR, the aircraft can't hold climb speed or a normal climb rate above ~10,000 ft while Live Weather is on. Turning off Live Weather fixes it right away. I haven't seen this in non-INI aircraft, so I'm reporting it here before opening a ticket with Asobo/MSFS. Build: 1.2.6 Steps to reproduce Load the A350-900ULR at VOHS with Live Weather on (29 Sept 2026, ~12:00 UTC). Depart with TOW: 414.3, ZFW 350.5, fuel 65.2, CI 160, thrust levers in CL. Climb through ~10,000 ft MSL toward FL410. Watch TAT/SAT, speed, and vertical speed. Workaround Turning off Live Weather makes TAT drop sharply, and performance goes back to normal. Turning Live Weather back on makes TAT go back to a level which is unrealistic for that altitude. Live weather disabled: Live weather enabled: