Hi Roro, good to see fellow South Africans on here.
This December past I was diving in 17/18 degC water at "Die Eiland" wich is quite exposed to the open ocean. If you go on Google maps you will see some rocks going into the ocean from the "Groot Paternoster Nature Reserve". These temperatures depend a lot on the ocean currents but some bays are a lot warmer. Over December we ski and tube in the Britannia Bay and on 2 occasions took their wetsuit off as it was just too hot. Cold water is not the end of the world.
All my friends dive with 5mm open cell suits, I started out with my Reef Pro-Diamond 4.3 surf suit and said I'll go buy an open cell suit when I realise I'm too cold. Reef hoodie, socks and gloves complete my suit. 2 weeks ago I was shorediving in 13degC water and after an hour in the water I was still fine. I guess I'm less susceptible to the cold. I love the freedom of movement, my suit fits me very well.
Going spearfishing we will either do a shoredive and spend about 60-90mins in the water, I still don't feel the need to buy a thicker suit for that.
When we go out on a boat and explore "die eiland" and other spots around the coast we spend 20-30 mins in the water at each spot, doing that the whole day and the wind chill on the boat gets to me at the end of the day.
I'm hesitant to go for a thicker suit as I love the fact that I don't need much weight, only 3,2kg for deeper than 5m, if max depth is 7m I add another 800g.
I'm in the process of buying a boat and want to get my friends into the freediving side, get good training in for spearfishing.
My girlfriend is also keen, she has all the gear and has been diving with me for a while. We did a Freediving course in Thailand when we were on holiday there.
I don't know how to link the viideo itself but check out my instagram, scroll down and you'll find a video of some spearfishing at "die Eiland"
https://www.instagram.com/adri.3333/
Let me know if you ever want t come brave the cold water and visit the West Coast!