Translation:The tea is cold.
A native speaker in another thread was saying that for ごはん[は/が]あついです, using は was acceptable to say the rice (the rice in front of you) is hot, while が was more forceful and had implications e.g. that the rice was too hot to eat yet.
Depending on the context, a (noun)は(adjective)です sentence could be saying all nouns are the adjective in general, but it's unlikely somebody would actually be wanting to say that all tea in general is cold
Hope this helps