I used to use sunscreen 7 days a week, 365 days a year, believing it to be the best thing to protect my skin. Then I learned that it is SO full of horrendous chemicals that now I NEVER use it. I live in QLD and I work as a landscape photographer so I am outdoors quite a bit. And I never use it.. and I never burn. It's really bad for vitamin D deficiency which most Aussie's have now.
You're lucky. I once got sunburnt spending about 15 minutes hanging out the washing at nine o'clock in the morning. I'm in Queensland too. Sometimes the UV here is extreme and melanoma remains a very real risk.
If I'm going to be outdoors a lot during the day I wear sunscreen and/or cover up with long sleeves, sunglasses and a hat regardless what time of year it is. I live in Queensland, under the hole in the ozone layer so it's important here, especially if you're very fair skinned like me. The UV can be high even when it's cold or overcast. I wouldn't bother on a day when it's actually rainy or if I'm just going to be outside for a few minutes.
I try to be vigilant regarding this but I must admit I tend to run a bit hot and cold on this, and there is plenty of room for improvement.
I do believe that the sun should be respected whatever the season.
Having had a melanoma on my face, I possibly should but would not think of doing it when it is overcast and not hot.
I walk my dogs every morning and even in summer I do not do it as I figure it is early and the sun will do good at that time.
I was told once that I needed more sun, and I believe that millions of people suffer from a lack of Vitamin D and the best way to get this is in the sun when the sun is not so strong. Otherwise you could end up with osteoporosis so I do not think sunscreen is a good idea in winter.