Confusing words 2
It's December and it's ten degrees centigrade outside. That is hot for this time of the year.
Actually, most students know the answer to this one as I’m sure warm and hot both appear in their languages: it’s just remembering which one to use at the right time and context.
Hot means ‘to be at a high temperature’, but it is usually referred to in the context meaning ‘when your body begins to feel uncomfortable with this temperature’, perhaps when you start to sweat: I’m hot. Or when you could burn yourself: Don’t touch that! It’s hot! Or when the weather reaches a point that you can sit outside but may, perhaps, require suncream, or the temperature has reached a point where it is uncomfortable: I’m staying inside, it’s too hot. In short, anything that might burn us or make us uncomfortable is hot: Venus is the hottest planet. It can be very hot in a steelworks.
Warm, however, depends on the context. In the Collins Cobuild dictionary, it means ‘to have some heat but not enough to be hot’. You can put on a warm sweater, it can be warm outside, or it can get warm in the office, meaning ‘to the point that we might need to open a window or put on the air conditioning soon’. However, it can also be used to describe something that is probably cold from our perspective, but if it is a few degrees higher or more than normal it is then considered warm, even though to our bodies this may still feel cold: The temperature at the North Pole is minus twenty-five degrees. This is considered warm. (The temperature is usually a lot lower than minus twenty-five degrees.) At ten degrees, December is warm for this time of year. Our planet is warming up. (Analyses suggests that the Earth is increasing in temperature. But if it was hotting up, then we should be very concerned!)
As an extra note, cool and cold are the opposites: if something is cold, this means to be at a low temperature: Minus twenty-five degrees may be considered warm at the North Pole, but that’s still very cold for me! Cool means to be ‘at a low temperature but not to the point where it is cold’, and again needs putting into context: Food is kept cool in the fridge. Twenty degrees in Singapore would be considered cool.
Finally, on a cultural note, most Brits tend to say 'centigrade' rather than 'celsius', but this is just simply a choice. There is no rule on which to use.