June 25 (Reuters) -Cotton prices extended gains to hit a more than three-week high on Tuesday, helped by short covering as investors looked forward to the key acreage report from the U.S. Department of Agriculture (USDA) due later this week.

* Cotton contracts for December CTZ4 rose 1.39 cent, or 1.89%, to 74.78 cents per lb at 12:15 EDT (1615 GMT), after hitting its highest since June 3, earlier in the session.

* "Speculators are almost record net short and we're kind of up on that," said Keith Brown, principal at cotton broker Keith Brown and Co in Georgia.

* "The weather is beginning to turn adverse... so I just think you're seeing that and positioning ahead of the acres numbers that come out on Friday," Brown added.

* Cotton speculators increased the net short position by 8,194 contracts to 51,442 in the week to June 18. CFTC/

* Focus this week will be on the U.S. Department of Agriculture's annual acreage report, to be released at noon EDT (1600 GMT) on Friday, June 28.

* Extending support to the natural fibre, the Nasdaq and S&P 500 are up on gains in Nvidia and other AI-related stocks. .N

* Elsewhere in the grains market, Chicago wheat futures eased while soybean and corn futures fell. GRA/

* In a weekly crop progress report on Monday, the USDA said 56% of the cotton crop was in good-to-excellent condition, compared with 54% a week earlier.

Reporting by Anmol Choubey in Bengaluru; Editing by Devika Syamnath