Launches out of Vandenberg in California are generally into high inclination orbits (like polar and near-polar) rather than retrograde. Per NASA:

Launches from Vandenberg have an allowable launch path suitable for polar insertions south, southwest and southeast. The launch limits at Vandenberg are 201 and 158 degrees. At a 201-degree launch azimuth, the spacecraft would be orbiting at a 104-degree inclination. Zero degrees would be due north of the launch site, and the orbital trajectory would be within 14 degrees east or west of the north-south pole meridian. At a launch azimuth of 158 degrees, the spacecraft would be orbiting at a 70-degree inclination, and the trajectory would be within 20 degrees east or west of the polar meridian. Like KSC, Vandenberg has allowable launch azimuths that do not pass over habitable areas or involve safety, abort, separation and political considerations.

The upcoming Sentinel-6 mission is headed for a 66º inclination orbit. I assume this means the booster will launch near the 158º azimuth and will "dog-leg" the remaining few degrees to the final inclination during the ascent and orbital insertion. Sentinel-6 is not particularly massive (~1.5 tons) and not going to a particularly high orbit (1336 km), so the Falcon 9 will have plenty of performance to spare to do this.

Launches out of Vandenberg in California are generally into high inclination orbits (like polar and near-polar) rather than retrograde. Per NASA:

Launches from Vandenberg have an allowable launch path suitable for polar insertions south, southwest and southeast. The launch limits at Vandenberg are 201 and 158 degrees. At a 201-degree launch azimuth, the spacecraft would be orbiting at a 104-degree inclination. Zero degrees would be due north of the launch site, and the orbital trajectory would be within 14 degrees east or west of the north-south pole meridian. At a launch azimuth of 158 degrees, the spacecraft would be orbiting at a 70-degree inclination, and the trajectory would be within 20 degrees east or west of the polar meridian. Like KSC, Vandenberg has allowable launch azimuths that do not pass over habitable areas or involve safety, abort, separation and political considerations.

The upcoming Sentinel-6 mission is headed for a 66º inclination orbit. I assume this means the booster will launch near the 158º azimuth and will "dog-leg" the remaining few degrees to the final inclination during the ascent and orbital insertion. Sentinel-6 is not particularly massive (~1.5 tons) and not going to a particularly high orbit (1336 km), so the Falcon 9 will have plenty of performance to spare to do this.