My wet/dry Shop Vac has a removable blower for double duty. Quick detach, swap the exhaust port for the blower nozzle and away I go. No worries on water on the garage floor because all my outlets are GFCI.
Since I always have a decent coat of something on the vehicles there's very little residue to mop up. I go around the vehicle with a WW in one hand and a utility MF in the other for door jambs, wheels etc after blowing it off. Probably no time saved but blowing out the nooks and crannies prevents that residual trickling the first time you drive it... really a bonus if you're going to polish or wax because you don't have to fight with any residual water. Another plus is no wringing out towels.
Regardless of the weather I always wash in the garage. I see pics of people washing cars out in the sun and I don't have a clue how they do it! I gritted my teeth in the last house and swore if I ever built I was gonna have multiple hose bibs, basin, drains and hot n cold running water in the garage. Around January in NE Ohio I'm kinda happy I went for the 75,000 BTU Reznor and insulation too.

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TL <--- the clean cars in the winter too guy