怎么用汉语说 ”early/mid/late 20's" 或 “low/mid/high" 20's"?
For early/low 20s
I'm not very sure about the EXACT ranges (if any) that &quot;early 20s&quot; and &quot;low 20s&quot; refer to in English.
But in Chinese, you may at least have three options to choose from, according to &quot;how early/low&quot; the range that you intend to express is:
early 20s
20多岁 or 20来岁 or 20岁出头
low 20s
20多度 or 20来度 or 20度出头
e.g. A weather forecast broadcast by CCTV in which &quot;5度出头&quot; was used at 1:01, another one in which &quot;20多度&quot; was used at 0:45
There must be some disagreement among native speakers as to what the exact ranges the expressions above refer to (they are not rigidly defined), but I believe generally one will feel that the range gradually turns narrower from left to right. (e.g. 20多岁 → 21 to 25; 20来岁 → 20 to 23；20岁出头 → 20 to 22 or even lower）
Besides, the patterns mentioned above are fairly productive in Chinese:

multiples of ten + 多/来 + unit
e.g. 30多天, 20来吨 (We don't say 32多天 or 25来吨)
number (it doesn't have to be multiples of ten, but the nuance is a bit tricky, see exmaples below) + unit + 出头
e.g.
25米出头(a little bit longer than 25m, must be shorter than 26m, since the scale is 25m - 26m),
20米出头(a little bit longer than 20m, can be even longer than 21m, since the scale is 20m - 30m).

For late/high 20s
I agree with Marc that 将近30度/岁 or simply 近30度/岁 (in literal: near 30) can be used.
For mid 20s
I agree with Marc that there may not be a handy phrase for that. However, I think you can alternatively say 25度/岁左右 or 25度/岁上下 (in literal: around 25).