Qkimbrell

My wife's Rx 330 has 150k. Very well maintained by a shop that only works on Toyota Lexus and Scion. The A/C just stopped blowing cold. Fans blow, cabin filter changed about 4-5 months ago. Coolant is fine. No record of A/C service or repair. Tried the cabin circulate button. It will blow hot air but not cold. So could it need recharged? Go hot in one day? I thought it would gradually get less cold. It went from Arctic cold to whatever the air outside was. A/C relay? Any help would be great!