Hi, in damper weather you will want to use a biltong box (if you want to make one) with a 60 or 100 watt light to provide warmth to dry the air - and preferably also a fan to better circulate air. If you don't have a biltong box to dry the meat you can also make biltong in your oven - make the pieces smaller (thinner), set oven to lowest temp setting (usually 170 degrees) and leave the door open a crack to circulate air. The oven method will only take 4-6 hours depending on the thickness of the meat. It's not exactly the same but gets you pretty close!
Here is a quick info graphic on making biltong found at www.biltongblog.com (the site has more biltong recipes and also more detail on biltong boxes, dehydrators, South African recipes etc.).
Enjoy!!