Winter wedding wear

I have an excuse to buy a new dress! Josh’s brother is getting married at the end of November (I designed the invitations for them), so I need a pretty cold-weather-appropriate dress. I’m hoping to find something in San Francisco, but here are a few backup options. I’m leaning towards the pretty grey number from Monsoon, teamed with a blazer and wedges for comfort. What do you think? Any tips for cover-ups and legwear?