The number of tropical cyclone landfalls in east Asia may be below average this year due to weak El Nino conditions.

The number of cyclone formations for the six months from May 1 is estimated at about 18, but fewer than eight are expected to cross coastlines, the Guy Carpenter Asia-Pacific Climate Impact Centre says.

The 1977-2018 average is for 16 formations, of which about 11 make landfall, according to the centre, based at the School of Energy and Environment at City University of Hong Kong.

Japan and South Korea landfalls are forecast below the average of 5.2, while eastern China and Taiwan coastal impacts may be below the average of 3.8.

Japan was particularly hard hit by severe weather last year, with the strongest typhoon in 25 years causing extensive damage in September. In other regions, near-average landfalls are forecast for south China and for Vietnam and the Philippines.

The assessments reflect relatively warm sea surface temperatures, which are likely to contribute to weak-to-moderate El Nino conditions for several months in the middle of the year.

The centre will run its model in September and October for the upcoming Australian cyclone season.