"Demand is high in this season."
Translation:La demande est forte en cette saison.
Il a tort de dire, <<La demande est haute en cette saison>>? Si, oui, pourqoui?
At a guess, it can be assumed "this season" of high demand is "peak season" - often called "haute saison". This is also most likely the use of the adjective forte - which also means strong. Imagine la demande est haute en haute saison. A bit repetitive.
I have seen haute used with demand but it is usually in relation to the economy.
Because haute demande (literally high demand) doesn't make sense in French. The only way I could understand it is as a demand by high society. Also as Ripcurlgirl says, you can see it in economy papers where the demande is represented by a value, which can indeed be high or low.
Even though it told me to use 'fort' previously, I used it and now it's saying to use 'elevee'. Not helpful.
You needed forte → feminine → as it is referring to la demande. I don't know why it has given you élevée but this is another feminine adjective meaning "high".