It's "surroundings are". Since the noun "surroundings" only has a plural form, it requires a verb in the plural.

It's "surroundings are". The noun "surroundings" only has a plural form and requires a verb in the plural.

The surroundings are really nice.

The surroundings is really nice.

Follow the same rule with other verbs to say, for example, "the surroundings have" (not "the surroundings has").

The city's surroundings have become increasingly congested.

The city's surroundings has become increasingly congested.

Be aware that "surrounding" (without "s") is an adjective, not a noun.

We explored the surrounding countryside.

Plural nouns, like "surroundings", take a plural determiner or pronoun.

Those surroundings are positive. They promote creativity and inspiration.

Be also aware that you cannot use the indefinite article "a" before plural nouns.

The surroundings were beautiful.

Follow the same strategy with other plural nouns, including "suburbs" and "outskirts".