As I suggested on a parallel reply, could you say a bit more about why you feel it makes sense, perhaps with a chart like the one I wrote up?
110 - sauna is too hot
100 - water boils in one atmosphere
50 - desert hot (record is 56.7 °C (134.1 °F) Death Valley, California, U.S.A. 10 July 1913)
30 - hot (for a finn)
25 - nice hot
20 - use more clothes below this
0 - water freezes, ice forms on roads, lakes etc.
-10 - cold but OK with good clothes
-20 - this starts to be so cold were you need to prepare yourself well if you want to spend more than an hour outside. Temperature inside freezer.
-30 - extreme colds start. You don't enjoy this even when prepared and using good clothes.
-40 - Winter War conditions
-50 - record breaking extremes
−89.2 °C (−128.6 °F) Vostok Station 21 July 1983
-110 Kriotherapy room for treating joint inflammation
We (and most things we eat, and all that white shitty stuff that blocks your commute in a winter day) are made mostly of water. The difference between -1C and 1C can be pretty significant, unlike the difference between -1F (fucking cold) and 1F (duh, fucking cold).
* Well, of course all of this is silly pissing match between groups of people who grew up with their favorite measure system, but anyway...
40 (as a max) was a not overly bad summer day
100 - Boiling water, cuppa tea
50 - Lawrence of Arabia
25 - The Great British Summer! Won't last, anyway
12.5 - Wear a jumper
6.25 - Wear a parka
0 - water freezes
-6.25 - Heathrow shuts down
-12.5 - Daily Mail reports weather causes cancer
-25 - Coldest reported weather in the UK
-50 - "I am just going outside and may be some time"
Maybe I'm missing out on something but I never felt the need for a chart.