METALS-Aluminium hits 3-month low as caution before Fed hurts metals

* Aluminum hits lowest since mid December at $2,069/T

* LME/ShFE arb: http://bit.ly/2wZSAEz

* GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Updates throughout, adds LONDON dateline)

LONDON, March 19 (Reuters) - Aluminum hit its lowest since mid-December on Monday as base metals wilted along with other cyclical assets before an expected interest rate hike from the Federal Reserve this week, and as finance ministers met for a G20 summit.

Alongside concerns that higher interest rates could dampen growth, U.S. President Trump's announcement of import tariffs on steel and aluminum has sparked fears of a global trade war which could weigh on demand for raw materials.

"Anything that undermines global growth will undermine metals consumption," Societe Generale analyst Robin Bhar said.

Aluminum, which has seen sharp increases in stockpiles in recent weeks as cuts to Chinese smelting capacity came to an end, slipped to its lowest since mid December.

"We've seen some big stocks builds on the London Metal Exchange and, more importantly, the Shanghai Futures Exchange, and that's the root of the problem," Bhar said. "It must be that the winter cuts were not as deep as the market had been expecting, plus demand must be weaker than originally thought."

* ALUMINIUM PRICES: LME three-month aluminum slipped to its lowest since Dec. 19 at $2,069 a tonne, and was at $2,078.50 a tonne by 1030 GMT, down 0.3 percent.

* GLOBAL MARKETS: Shares were stuck on their worst run since November as caution gripped traders in a week in which the Federal Reserve is likely to raise U.S. interest rates.

* G20: Worries about the potential for a U.S.-China trade war and frustration over U.S. President Donald Trump's steel and aluminum tariffs threatened to dominate the G20 gathering of finance leaders.

* ALUMINIUM STOCKS: Shanghai aluminum stocks surged 87,303 tonnes to a record 934,216 tonnes, data on Friday showed <AL-STX-SGH>. Stocks of the metal in LME warehouses <MALSTX-TOTAL> fell 12,250 tonnes, according to data released on Monday, but are still up 22 percent from their early February lows.

* COPPER: London Metal Exchange copper was 1.1 percent lower at $6,815 a tonne, extending losses from Friday when prices fell half a percent. Prices earlier dropped to $6,785, which was the weakest since March 9.

* INVESTORS: Hedge funds and money managers trimmed their net long positions in COMEX copper contracts in the week to March 13, regulatory data showed on Friday.

OTHER METALS: LME zinc was down 0.2 percent at $3,252 a tonne, while lead was 0.7 percent lower at $2,365.50 a tonne. Nickel was down 1.4 percent at $13,430, and tin was down 0.5 percent at $20,905.

(Additional reporting by Melanie Burton in Melbourne Editing by Edmund Blair)