It’s rather too late to put piggies who are used to being indoors outside. If you’re not getting them for a month or two and they’ve only ever been inside, then it would be best to keep them inside until next spring when the nights are warmer, or wait until next spring to get them.
They will need a strong predator proof hutch made with thick wood which is ideally off the ground. A c&c playpen is not suitable for outside. A playpen needs to be made from wood and fine gauge mesh so nothing can get inside of it). They can’t be in a run/playpen when it is wet or cold (the guide is if you feel cold standing on the ground with bare feet, then it is already too cold for the piggies), so the hutch needs to be big enough to give them plenty of space to run around
For keeping warm in winter, they will need a thick layer of hay, snuggle safe heat pads are essential, thermal and waterproof hutch covers. Also the hutch to be in a sheltered position and where possible the hutch put in a shed/garage/outbuilding for winter. If it was to be a bad winter, a plan to bring them indoors is needed for every winter (and once they’ve had to be brought in, they need to stay in for the rest of the winter as piggies can’t cope with large fluctuations in temperatures )
For summer, again a sheltered shaded position. Hutches get hot even in the shade. Plus you’ll need a plan to bring them indoors if it is too hot.be
Mine live in a hutch in a shed year round. They have access to play in the shed during daylight hours, a wooden outside run plus I have extra c&c grids for an indoor playpen for times when it is too cold or too hot for them to be outside. Keeping them at the right temperature takes a lot of work but it is possible to do provided they have enough protection and a heat source in winter.