It looks as though summer has arrived on Tynemouth beach on England's northeast coast—but this photo was taken in early February.

Britain, like other places in northern Europe, has experienced one of its mildest winters ever, in stark contrast to other parts of the Northern Hemisphere.

Swallows that normally migrate to Africa in the fall have been found spending the winter in the United Kingdom for the first time, according to researchers.

Scientists also discovered bluebells in bloom almost two months early in the south of the country.

The balmy conditions are likely due to the influence of the North Atlantic Ocean, according to Simon Boxall of the U.K.'s National Oceanography Centre.

The so-called North Atlantic Oscillation is controlled by Atlantic pressure systems that have pushed warmer waters farther north than usual this winter, Boxall said.

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