A compromise — #16 of 31 Flannel ranks #16 of 31 fabrics for night sweats. It is a middling fabric for this. Ranked on breathability and moisture absorption, penalised for warmth and weight. The top pick is Linen.
Flannel measures 58/100 for breathability, 12% moisture regain, 80/100 warmth, at 260 gsm. For night sweats, modest breathability and strong moisture absorption decide comfort — and its higher warmth risks trapping heat against the skin.