A 300 GSM comforter seems like a practical choice for someone looking for a balance between warmth and lightness. The actual comfort will also depend on the filling and fabric, since breathable materials can make a big difference for people who sleep warm. I’d also look at the whole bedding setup rather than the comforter alone. During warmer months, sweat and moisture can reach the mattress, so using a
zippered waterproof mattress cover alongside a breathable comforter can help keep the mattress protected while maintaining a clean and comfortable sleeping environment.