I don't know why "conditions" should be used here? why not "condition"? Do they have different meanings?
Native speaker’s answer
Rebecca
They do have slightly different meanings! So, "condition" is a countable noun, and the plural form is "conditions." They say "conditions" since multiple aspects lead to a warm environment. If there were only one of those aspects, then "condition" would be used. Generally, when speaking about the environment, multiple factors lead to an overall type of "condition," which is why the plural form is used. Ex: The conditions are cool outside due to the wind and declining temperature. Ex: You have to leave the plant in warm conditions. => common use Ex: A normal condition for growing plants is to have it near the window for sunlight. => "a condition" is used less