Italian grammars call the if-sentence the periodo ipotetico, and sort it into three types. The first is the periodo della realtà: something that may well happen.

Se + presente → presente, futuro or imperativo

• Se piove, restiamo a casa. — If it rains, we'll stay at home.
• Se vieni stasera, ti preparo la pasta. — If you come tonight, I'll make you pasta.
• Se hai fame, mangia qualcosa! — If you're hungry, eat something!

Where English never puts will after if, Italian can use the future in both halves: Se domani pioverà, resteremo a casa. Both versions are correct; the present is more common in speech.