SINGAPORE, June 17 (Reuters) - Chicago wheat futures slid about 1.5% on Monday to their lowest levels in six weeks, as pressure from rapidly advancing winter crop harvest in the United States added pressure on prices.

Corn lost nearly 1%, while soybeans were down 0.4%, with focus on the weather in the U.S. Midwest.

FUNDAMENTALS

* The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 1.4% at $6.04 a bushel, as of 0011 GMT, having hit its weakest since May 3 at $6.03 a bushel earlier in the session.

* Corn lost 0.9% to $4.45-3/4 a bushel and soybeans gave up 0.4% to $11.75 a bushel.

* Traders are monitoring U.S. weather as corn crops approach a key development period in July, while winter wheat harvesting is gathering pace.

* In the Black Sea region, rain in dry parts of Russia and Ukraine provided some relief for corn, though benefits may be limited for wheat with harvesting looming, analysts said.

* The U.S. Department of Agriculture (USDA) cut its wheat production estimates for top-exporter Russia and Ukraine this week following drought and frosts.

* Crop conditions for soft wheat in France were steady last week, data from farm office FranceAgriMer showed on Friday, but harvest prospects in the European Union's biggest producer remained poor after a damp growing season.

* Conditions in the U.S. Crop Watch corn fields have been below average so far this season, and while last week's warmth perked up some fields in the western Corn Belt, the eastern fields will face scorching temperatures this week, Karen Braun, an analyst for Reuters, wrote in a column.

* "Crop health remains perfect in Indiana and Ohio, but plunged this week in southeastern Illinois after a second week with no rain. Conditions in all three locations could decline next week as the heat will be accompanied by little or no rain."

* The USDA is slated to release weekly crop-progress data for U.S. corn and soybeans later on Monday, and some analysts said they expect slight declines in good-excellent condition ratings.

* Traders are also waiting for the USDA to issue U.S. plantings and quarterly stocks data on June 28.

* Large speculators trimmed their net short position in Chicago Board of Trade corn futures in the week ended June 11, regulatory data released on Friday showed.

* The Commodity Futures Trading Commission's weekly commitments of traders report also showed that non-commercial traders, a category that includes hedge funds, increased their net short position in CBOT wheat and increased their net short position in soybeans.

MARKET NEWS

* U.S. stocks dipped, gold surged and European stocks suffered their biggest weekly loss of the year on Friday amid cooling economic data, a hawkish Federal Reserve and unfolding political crises in Europe.

DATA/EVENTS (GMT) 0200 China Urban Investment (YTD) YY May 0200 China Retail Sales YY May 0200 China Unemp Rate Urban Area May n/a UK House Price Rightmove MM, YY June (Reporting by Naveen Thukral; Editing by Sherry Jacob-Phillips)