Learn Portuguese (Portugal): Nós temos calor.

In Portuguese, you use the verb ter (to have) to describe feeling hot, cold, hungry, or thirsty. You are literally saying "We have heat." English uses "to be" for these feelings, but Portuguese uses "to have."

Can I translate "We are hot" literally and say "Nós estamos quentes"?

You should avoid this! In Portuguese, using estar or ser with quente for a person usually means they are physically hot to the touch, and it often carries a sexual connotation. Always use ter calor when you mean the weather or room is making you feel hot.

Do I have to include the word "Nós" at the beginning?

No, it is completely optional. Because the verb form temos is only ever used with nós, Portuguese speakers often drop the pronoun and simply say Temos calor.

If a group of women is speaking, does "calor" change to match their gender?

No, it stays exactly the same. Calor is a noun meaning "heat," not an adjective describing the women. Because it is a noun, it does not change its ending to match the people who have it.