http://www.zarya.info/GoForLaunch.php reports launch is delayed to Apr 24 21:02:13 UTC from Apr 22 by strong winds at the launch site. (Sentinel 1B, Microscope, OUFTI 1, E-ST@R II and AAUSat 4 Launch)

http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Senti nel-1/Watch_live_Sentinel-1B_launch reports the same: Although launch was originally scheduled for 22 April at 21:02 GMT (23:02 CEST), liftoff has been postponed owing to weather conditions. The aim is for the launch to take place at the same time on 24 April. The launch can be followed via live webstream.

Henk, PA3GUO