What does "it feels like negative thirty degrees" even mean? 30 F is chilly but okayish and 0 F is miserable. If 30 F to 0 F is as 0 F is to how it feels now, why am I not screaming in agony?
As a corollary, a typical day has some wind so "feels like thirty deg" will mean something like "it feels like 30 deg w 5 mph winds." This implies a windless 30 deg day that feels like 35 deg. Is negative wind chill possible?