BEIJING, June 17 (Reuters) - Prices of copper opened lower this week after China's May industrial output data missed forecasts, while a firm U.S. dollar also weighed on the metal.

Three-month copper on the London Metal Exchange was down 0.2% at $9,724 per metric ton by 0248 GMT, having had a flat week previously.

The most-traded July copper contract on the Shanghai Futures Exchange slid 1% to 78,880 yuan ($10,872.35) a ton.

China's May industrial output lagged expectations with the still-weak property sector, which is also a major consumer of industrial metals.

However, retail sales accelerated last month.

Prices of copper, often seen as an economic bellwether, jumped in May to record highs on speculative buying amid raw material shortages, followed by downward corrections as China's demand proved weaker than expected.

The dollar was firm on Monday as the euro hovered near a more than one-month low amid continued concerns about the political outlook in Europe.

LME nickel climbed 0.3% to $17,620 a ton, aluminum dipped 0.2% to $2,513.50, tin added 0.9% to $32,600, zinc advanced 0.7% to $2,788 and lead rose 1.3% to $2,166.50.

SHFE nickel declined 0.6% to 136,560 yuan a ton, aluminum decreased 1.2% to 20,420 yuan, zinc lost 1.4% to 23,350 yuan, and tin dropped 1.2% to 268,200 yuan, while lead gained 0.8% to 18,705 yuan.

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($1 = 7.2551 Chinese yuan renminbi) (Reporting by Siyi Liu and Colleen Howe; Editing by Sonia Cheema)