y pigs have their Pighouse (DCs old wooden playhouse) and they do indoor/outdoor in Winter. IIRC they came indoors for nights around Guy Fawkes (and I'm scanning the weather reports to see when I can get them out again. Love you dearly girlies but I need to vacuum the carpet without your cage there 
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Raised off the ground is best, it gives them protection against damp, passing cats but you need to be careful when you open the door, they ain't the sharpest tools, they can fall out.
The two level hutches with a run- difficult to move if you want fresh grazing. Guineas sometimes struggle with ramps. And though the idea of giving them the freedom to choose, sometimes it's not suitable for them to go out if it;s been raining. So they'd risk damp bellies.
For an outdoor hutch, get the biggest you can. Position in a non draughty, out of direct sun area. If you can, near the house. Fix it securly so it won't tip over.
You can buy waterproof covers which will protect against winds, but make sure they're ventilated.
You can increase the protection with extra wire mesh , extra bolts and flymesh on the outside.
A moveable run so you can give them fresh grass (secured with tent pegs in the grass) and a shade Look on the Bunny Business site, they do nice , metal runs that can fold up.
Next week the overnight temps are 2-3c.
During the Easter holidays it;s predicted to be 7c overnight so I might put them out 24 hours then.
They'll have their small heater on low and a Snugglepad and a load of hay to keep them cosy .
Any change needs to be gradual. Maybe start putting them out in the day when it;s warm, but still bring them in at night until it gets warmer. Ours sleep in a 2'x4' cage at night (very judgily) though GP3 (neutered boar) and GP4+GP5 fared better than our two boars .
We put them in the Pighouse to give them runabout space -floor covered in equine bedding (chopped cardboardy stuff) and soft barley straw . Haybox full of hay daily. But the temperature in the night bedroom and the Pighouse had to be similar.