On Sunday I thought I'd have a bimble out as it was a nice enough day. I store my Vespa in a garage and it's also covered. Upon uncovering the scooter it was very damp, borderline wet with what I assume was condensation. I've never seen this before and I've used the same cover for a couple of years ish. I have now left it on covered but I do like something over it, does anyone have suggestions for a cover which will not cause this issue?

I use an old double bed sheet. Breathable, lightweight, cheap and easy to store.

It may have been a weather phenomenon. I've seen something similar with the car that you find running with condensation even though its been in the garage. It may be something to do with the rapid rise in temperatures on Sunday. The garage would have retained its cold air for longer, so warmer damper air outside might have condensed onto the scoot when they mingled. Says he, bullsh!tting firmly! But I have seen this before.

Stibbs, that's a good idea! Mr Grumpy, you could be correct, as I said I've never seen it before!

Agree with Mr Grumpy
Noticed this many times myself. Living on the coast, so subject to sudden differences in temp. Usually after a longish cold spell, then when a warm front moves in holding more moisture, it causes condensation to from on any cold surface.
Have my bike covered with old mattress protectors and a motorcycle cover, helps somewhat as only the uncovered parts get condensated.
Had a friend who had several bikes and used to cover his bikes with old "donated" continental quilts and none of his bikes ever suffered corrosion, treat them like babies

Mattress protector sound like a plan!

Get yourself a decent cotton dust sheet from B&Q. That's what I use. Works well & very cheap.

Tucano Urbano cover excellent for preventing condensation

Why cover it at all in the garage? I don't and it avoids potential condensation problems as mentioned. The bike will probably attract some dust over time but that's easily wiped off, which is preferable imo to the risk of condensation which can have nasty effects if left too long.

I always keep my bikes covered in the garage, which is integral with the house, has an up-and-over type metal door and can be draughty around the edges in winter. I use multiple layers of old cotton/polycotton sheets, which I would have no other use for anyway. There's never any moisture, the sheets keep dust at bay and should you have a slight accident passing-by, or getting something from a shelf etc provides a modicum of light protection. Additionally, if you have the garage door open whilst doing something, the covers help obscure the view of the prying eyes of the local thieving scrap merchants! I have a lightweight vinyl cover too, but this is only used when overnight parked away from home on a visit to somewhere.