Adam Clarke on 1 Kings 18:1

After many days - in the third year - We learn from our Lord, Luk 4:25, that the drought which brought on the famine in Israel lasted three years and six months. St. James, Jam 5:17, gives it the same duration. Probably Elijah spent six months at the brook Cherith, and three years with the widow at Sarepta.

I will send rain upon the earth - The word האדמה haadamah should be translated the ground or the land, as it is probable that this drought did not extend beyond the land of Judea.