The temperatures will climb up...,

[Silverobama]

It’s spring now but it’s still a bit cold. However, the weather forecast says that a few days later the temperature will be 30 degree Celsius. Now, it’s only 12 degree Celsius, but after stays at 30 degree it will drop to 12 again. I wrote a sentence to describe this phenomenon:

The temperatures will climb up to 30 to 32 degree Celsius within a few days but will soon drop back to 12 degree Celsius within one night.

Is the italic sentence natural?

 

[emsr2d2]

It’s spring now but it’s still a bit cold. However, the weather forecast says that in a few days later the temperature will be 30 degrees. Celsius. Now, it’s only 12 degrees Celsius, but after stays at reaching/hitting 30 degrees, it will drop to 12 again. I wrote a sentence to describe this phenomenon:

The temperatures temperature will climb up to 30 to 32 degrees Celsius within a in/over the next few days but will soon drop back to 12s degree Celsius within one night 24 hours later.

Is the italic sentence natural?

See above. You must remember to pluralise "degrees" when talking about temperature (unless the temperature is 1 degree C or F).
Once you'd established you were talking about Celsius, there was no need to repeat the word.

 

[mrmvp]

It’s spring now but it’s still a bit cold. However, the weather forecast says that a few days later the temperature will be 30 degree Celsius. Now, it’s only 12 degree Celsius, but after stays at 30 degree it will drop to 12 again. I wrote a sentence to describe this phenomenon:

The temperatures will climb up to 30 to 32 degree Celsius within a few days but will soon drop back to 12 degree Celsius within one night.

Is the italic sentence natural?

The temperature will climb from 30 to 32 degree Celsius within a few days but will soon drop back to 12C degrees within one night.

Rember, from 23 "to" 44. Between 23 "and" 44.

 

[jutfrank]

Silverobama means that the temperature will climb from what it is now to somewhere within the range 30-32 degrees.