Hmm, I have the same intuitive feeling with Celsius. I guess it depend on which temperature system you grew up with.
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.
50 Summer time
40 Average hot day
30 Average cool day
20 WTF is going on? Did hell freeze over?
It never goes below twenty.
Where do you live? The sahara desert?
BTW you seem to have a greek name but you definitely don't live in Greece! We do have some hot weather here, but definitely not in the range you described.