Workers and local volunteers carrying buckets wait in line to fetch white paint. (Xinhua/Purbu Tashi)

Winter may not be a perfect season for visiting Tibet, but you may have a chance to see how the 1,300-year-old Potala Palace in Lhasa is having its yearly facelift.

Painters at work. (Xinhua/Purbu Tashi)

It will take about a month to paint the palace, a UNESCO World Heritage Site, in preparation for "Lhabab Duchen," which falls on Nov. 20 this year. Lhabab Duchen is believed to be the day the Buddha descended from the heaven and is one of four annual festivals celebrating important events in his life.

Buckets filled with whitewash sit in queue on the ground. (Xinhua/Purbu Tashi)

The whitewash is concocted using a traditional formula of milk, honey, sugar and lime. The mixture has a distinctive sweet smell.

A worker splashes whitewash on the wall. (Xinhua/Purbu Tashi)

Painting of buildings on a regular basis is common in Tibet and a necessary protection against extreme weather conditions. Before Lhabab Duchen, many monasteries and local people's homes are also repainted.

A worker hung in the mid air sprays whitewash. (Xinhua/Purbu Tashi)

For more than 40 years, Tsetop, a Lhasa resident, has participated in the annual whitewashing. He also donates milk to the palace for the paint.

"The whitewash is heavy, but I am willing to offer my hand no matter how heavy it is. The more I carry, the more good deeds I do," said the old man.

An old woman with a bucket of whitewash on her back. (Xinhua/Purbu Tashi)

It was the first time that Degyi had taken part in the event. "I am decorating the Potala Palace on behalf of my family. It's my family tradition,"she said.

Volunteers wait to fill their buckets with whitewash. (Xinhua/Purbu Tashi)

The Potala Palace was built by King Songtsa Gambo in the seventh century and expanded in the 17th century by the Fifth Dalai Lama. It received more than 900,000 visitors last year.

The palace was included into the UNESCO World Heritage List in 1994.