Millions more people could face hunger and shortages if the drought, which is also being felt across the Middle East, takes hold, the United Nations agency warned.
If rains fail to fall by the time of the harvest in mid-May, food prices would soar and Syria would need to import more than the estimated 5.1 million tons of wheat needed during the previous season, WFP added.
"A drought could put the lives of millions more people at risk", spokeswoman Elisabeth Byrs told a news briefing in Geneva.
"WFP is concerned about the impact of a looming drought hitting the northwest of the country - mainly Aleppo, Idlib, and Hama, with rainfall less than half of the long term average (since September) and potentially major impacts on the next cereal harvest," she said, adding that barley output was also affected.
Up to 6.5 million Syrians could need emergency rations, up from the current figure of 4.2 million, Byrs said.
The WFP, which reached a record 4.1 million people with food rations in March, said on Monday that it had to cut the size of food parcels to hungry Syrians due to a shortage of funds from donors. REUTERS