The average or median is usually the idea.. But it's kind of a bunch of pointless numbers.. I mean growing in the "green zone" of plants is a pretty large ratio. Sometimes it helps diagnose if people have problems. Sometimes it just sends them further down the rabbit hole. Ie foliage problems are usually related to intake/transportation and not humidity as much as can be thought.. Sudden changes in climate can hurt plants... But plants acclimatize to their growing environment.. It's why you can grow in Russia, Canada, New Zealand, South America and Even Alaska and the Yukon. It's all about them acclimatizing and not having dramatic changes in climate.