How long did the drought that Elijah prayed for really last?

James and Luke say the drought lasted for three and a half years. >Elijah was as human as we are, and yet when he prayed earnestly that no rain would fall, none fell for three and a half years *(James 5:17 NLT)* >"Certainly there were many needy widows in Israel in Elijah's time, when the heavens were closed for three and a half years, and a severe famine devastated the land. *(Luke 4:25 NLT)* But according to the actual account in the Old Testament the drought was not even a full three years. >Now Elijah, who was from Tishbe in Gilead, told King Ahab, “As surely as the LORD, the God of Israel, lives—the God I serve—there will be no dew or rain during the next few years until I give the word!” *(1 Kings 17:1 NLT)* >Later on, IN THE THIRD YEAR of the drought, the LORD said to Elijah, “Go and present yourself to King Ahab. Tell him that I will soon send rain!” *(1 Kings 18:1 NLT)* >And soon the sky was black with clouds. A heavy wind brought a terrific rainstorm, and Ahab left quickly for Jezreel *(1 Kings 18:45 NLT)* So it was in the third year of the drought that the rains came ending it. Why do Luke and James both say the drought lasted 3 years and 6 months?