I would be inclined to keep him inside until he is a bit older, then I would let him stay outside.
I know the weather by you is generally ok - our dogs in JHB stayed outside all the time, they only came into the house for a few hours in the evenings when we got home from work.
Our little guy is now 10 weeks old, and he is currently kept in the house during the day. My folks are coming for a visit and will be here until he is 5 months old, whilst they are around he will be outside with them during the day and in the house when they go out, and after they go back home he will then start being kept outside during the day whilst we are at work.
I plan on taking him for walks, do some training and play some games for 1hr in the morning before work and then for a couple of hours in the evening after work.
He went for his injections today so I've got 10 days to wait and then I can start taking him out for walks.