The pilot of Solar Impulse 2 has said that the solar-powered plane is still waiting for an opening in the wall of clouds over the Pacific, weeks after an emergency landing in western Japan.

Solar Impulse 2, which is attempting an around-the-world flight, cut short the seventh leg of its 22,000-mile journey on 1 June due to bad weather. It landed at a small airport in Nagoya.

The team behind Solar Impulse 2 have had to postpone tentative departure schedules at least twice in the interim due to continued unsuitable weather conditions.

"The front we have from Taiwan to Alaska, physically it's like a wall. With this aeroplane we cannot fly through the front: it's too cloudy, it's too rainy, it's too bumpy, it will be too dangerous," co-pilot and Solar Impulse co-founder Andre Borschberg said in a news conference in Tokyo.

The plane has a wingspan as wide as the largest passenger airliner but the weight of a family car.

"So I'm looking for a place where the wall is, for example, only a meter or a meter and a half so that I can jump over as a person, and that's exactly the same I'm looking for for the plane," the 62-year-old former Swiss Air Force pilot said.

In the worst case scenario, Borschberg confirmed the departure from Japan will be next spring.

"We planned to fly in summer, so in the worst case if we could not find the weather window, we have to wait until spring comes back."

The plane, which has its wingspan covered in 17,000 solar cells, took off from Abu Dhabi in March with an ambitious plan to circumnavigate the globe powered only by the sun.

Overall, the trip was expected to span approximately 25 flight days broken up into 12 legs at speeds between 30 to 60 mph. Its journey across the Pacific Ocean – from Nanjing, China to Hawaii, USA – was expected to be the most difficult stretch of the journey.

The plane was known to have a minor damage on its aileron, specifically on a part called 'flattener', and the team had to ship a replacement part from Switzerland.

"It's not serious, but it takes time because you have to get parts from Switzerland, you have to change them, and of course afterwards you will need to re-calibrate and re-test everything," said Borschberg, adding that the technical problem was completely solved.

Borschberg is one of the two Swiss pilots who take turns at the controls in the tiny cabin for up to five consecutive days and nights in the air.