Oil hit a four-week high above $78 a barrel on Monday as colder weather across the United States and signs of economic recovery helped boost the outlook for fuel demand. Oil has risen more than 12 percent from a dip below $70 two weeks ago on expectations of rising consumption and falling inventories. A US government report last week showed a larger than expected fall in crude stocks.
"The market is getting support as a cold wave in the US Northeast is projected to boost demand," said Tomokazu Amano, an analyst at Mitsubishi Corp Futures & Securities in Tokyo.