Below zero is when air temperature starts to get hazardous
Hazardous in what sense? If you’re not wearing proper clothing, lower than 10C can be hazardous. Many hikers who get lost get hypothermia even if it’s above zero because they were dressed for an energetic hike, not sitting around waiting for a rescue.
If you are properly dressed, -10C is no big deal. Many people do outdoor sports for hours when the temperature is well in the negatives.
IMO, if you’re within 10C of ideal room temperature, you may be uncomfortable but you’re probably not in danger. But, if the temperature is above 30C or below 10C you need to take precautions: shade and water in the case of hot weather, warm clothing in the case of cold weather. I don’t think there’s anything special about 0C for humans, except for the fact it’s when water turns to ice, rain turns to snow, etc. If you have the right gear, 5C, 0C, -10C and -20C are all survivable, possibly even comfortable. You just need more and more specialized gear as the temperature gets lower.
Like I said, people who use Celsius know when to wear a coat.
So do people who use Fahrenheit.
But if we’re maintaining that 0 and 100 are special numbers, then Fahrenheit maps hazardous conditions more neatly to those numbers.
I completely disagree. 0 Fahrenheit is very cold, but there’s nothing special about that temperature. You need to start dressing for cold conditions long before it gets that cold, and if you dress for cold conditions you can easily handle temperatures well below 0F. 100F is also nothing useful. Yes, it’s very hot, but you start needing to take precautions for heat long before it hits 100F.
Basically the Fahrenheit scale has nothing particularly useful at 0 or 100F. The Celsius scale has useful things at 0C and 100C. 100C is not useful for weather, but 0C is very useful for weather because it tells you whether it’s likely to be icy out.
Hazardous in what sense? If you’re not wearing proper clothing, lower than 10C can be hazardous. Many hikers who get lost get hypothermia even if it’s above zero because they were dressed for an energetic hike, not sitting around waiting for a rescue.
If you are properly dressed, -10C is no big deal. Many people do outdoor sports for hours when the temperature is well in the negatives.
IMO, if you’re within 10C of ideal room temperature, you may be uncomfortable but you’re probably not in danger. But, if the temperature is above 30C or below 10C you need to take precautions: shade and water in the case of hot weather, warm clothing in the case of cold weather. I don’t think there’s anything special about 0C for humans, except for the fact it’s when water turns to ice, rain turns to snow, etc. If you have the right gear, 5C, 0C, -10C and -20C are all survivable, possibly even comfortable. You just need more and more specialized gear as the temperature gets lower.
Like I said, people who use Celsius know when to wear a coat.
But if we’re maintaining that 0 and 100 are special numbers, then Fahrenheit maps hazardous conditions more neatly to those numbers.
I don’t think 0 and 100 have as much special significance as people seem to think when it’s assigned to water.
So do people who use Fahrenheit.
I completely disagree. 0 Fahrenheit is very cold, but there’s nothing special about that temperature. You need to start dressing for cold conditions long before it gets that cold, and if you dress for cold conditions you can easily handle temperatures well below 0F. 100F is also nothing useful. Yes, it’s very hot, but you start needing to take precautions for heat long before it hits 100F.
Basically the Fahrenheit scale has nothing particularly useful at 0 or 100F. The Celsius scale has useful things at 0C and 100C. 100C is not useful for weather, but 0C is very useful for weather because it tells you whether it’s likely to be icy out.