Strong power demand during an unusually hot summer have driven Japan's coal imports to a 20-month high.

In September of this year, Japan imported 15.90 million metric tons of coal, a 17.35% year-over-year increase, according to the country’s Ministry of Finance.

Japan experienced its second-hottest summer on record this year, with some regions setting new temperature highs.

The average temperature across Japan in recent months has been 2.52 degrees Celsius above normal levels, according to the Japan Meteorological Agency.

The rise in temperatures has driven up electricity demand, prompting power plants to buy more coal from overseas.

Some commodities analysts say that Japan's increased coal consumption is not only due to warmer temperatures but also to weakening nuclear power generation, which is expected to continue moving forward.

Japan’s coal consumption is expected to continue rising as the country’s Meteorological Agency forecasts that temperatures will remain above the 30-year average in coming months.

Australia remains Japan's top %Coal supplier with 10.5 million metric tons imported in September, up 18.2% year-over-year.

Japan’s government says it is exploring alternative energy options beyond coal, including wind and solar power.

The burning of coal is viewed as contributing to the greenhouse gas emissions that cause climate change around the world.