Farm crops may be affected by the unusually cold weather in northern and western Japan since late June, the Meteorological Agency said Tuesday.

A particular area of concern is the Tohoku region, where the average high temperatures have been nearly 5 degrees lower than normal. Some locations have also experienced a type of cold called "tsuyuzamu," the agency said.

Tsuyuzamu occasionally comes during the rainy season, or "tsuyu," which starts in June in most of Japan.

The agency said a high-pressure system coinciding with the rainy season and centered over the Sea of Okhotsk has been stronger than usual.

As a result, the rain front in Japan has moved southward and spread, resulting in gloomy weather and reduced hours of sunshine.

The drop in temperatures, meanwhile, is due to a damp chill forced into Japan, mainly in the north, by high atmospheric pressure.

Temperatures have dropped mainly in areas of Tohoku facing the Pacific. The average high from June 24 to July 10 was 4.8 degrees lower than normal in Mutsu, Aomori Prefecture, and 4.3 lower in Miyako, Iwate Prefecture.

For both areas, the hours of sunshine were also less than in an average year, it said.

Sunlight hours were reduced for most of the other observation locations.

Likewise, average highs in the Kanto and Koshin regions in eastern and central Japan earlier this month were lower than normal. They dropped to 22.6 in Mito, Ibaraki Prefecture; 23.5 in Utsunomiya, Tochigi Prefecture; and 25.6 in Tokyo. Total hours of sunshine in these regions were fewer than usual as well.

The agency said the hours of sunshine in the Tokai, Kinki, Chugoku and northern Kyushu regions were much less than normal.

It may take longer than usual to declare an end to the rainy season, the agency added, but the normal hot and sunny days should follow.