BEIJING - China's coal output fell in July from June's record production, official data showed on Wednesday, despite strong demand from electricity utilities to power air conditioners during the hot summer months.

Chinese miners produced 322.23 million tonnes of coal last month, down 3.3% from 333.35 million tonnes in June but well above 281.5 million tonnes in July last year, data from the National Bureau of Statistics (NBS) showed.

Weaker production at domestic mines came as coal imports rose 21% in July from the previous month to 32.9 million tonnes. Imports rose even as China's customs tightened coal imports at several ports by delaying or even halting customs clearance.

Households and businesses typically crank up their air conditioning over the Northern Hemisphere summer, with temperatures peaking during July and August.

Output over the first seven months of 2019 was still up 4.3% from the same period last year at 2.09 billion tonnes, the NBS data showed.

Coal prices hit their highest this year on April 30, before retreating as Beijing asked miners to ramp up production. Coal futures on the Zhengzhou Commodity Exchange CZCcv1 have since fallen 6% to 577.6 yuan ($82.21) a tonne on Wednesday.

Approvals for new coal mine construction in China have also surged in 2019, government documents showed, with Beijing expecting consumption to rise in the coming years even as it steps up its fight against air pollution.

Power generation rose for a third month in July to reach 657.3 billion kilowatt-hours (kWh), up 0.6% on a year earlier. In the first seven months, China generated a total of 4.03 trillion kWh of electricity, up 3% on a year ago.

Production of coke, a key raw material for steelmaking, rose 5.9% in July on year to 39.61 million tonnes.

For the January to July period, coke output reached 274 million tonnes, up 6.7% from the same period last year, the NBS data showed.

($1 = 7.0259 Chinese yuan renminbi)

(Reporting by Muyu Xu and Shivani Singh; editing by Richard Pullin) ((muyu.xu@thomsonreuters.com; +86 010 66271298;))