Re-distribution after induction of anesthesia is the most important cause of perioperative hypothermia. The extent of re-distribution is proportional to the gradient between the core and peripheral compartments. Pre-warming increases the heat content of the peripheral thermal compartment, reducing the gradient for redistribution. Recently, A recent-meta analysis suggested that as a single strategy, preoperative forced air warming had significant benefits than other warming methods. Also, it was reported that only 20 (or even 10) min of pre-warming mostly prevented patients from perioperative hypothermia under general anesthesia. However, few studies have examined whether short time pre-warming can reduce hypothermia due to a large amount of irrigation fluid during surgery under spinal anesthesia.