In some kind of twisted logic, harsh weather conditions that impose considerable hardships often add to the lure of a place for visitors from afar.
So when earlier this month, temperatures in the northern province of Lao Cai Province dropped to a chilly four degrees Celsius forcing residents to add extra layers of clothing for their children and provide blankets and warm stables for their livestock, the tourists flowed in, excited to see the misty mountains and valleys and experience the cold.
Cao Huong, an intrepid traveller in her late twenties, was one of those who saw an opportunity in the colder than usual weather.
"After each cold wave," she said, "there will usually be a rise in temperature, and if you go up the mountains at this time, chances are that you can see the magnificent sea of clouds and capture it with your camera."
Indeed, members of online photography groups have been sharing tips on how, when and where extremely photogenic landscapes can enhance the experience of mountain climbing.
Fittingly then, it was amidst this cold wave that the northwestern mountainous province hosted the launch of the National Year of Tourism in the presence of Deputy Prime Minister Vu Duc Dam.
This year's campaign, themed "Colours of the Northwest", will see a series of activities and events designed to attract more visitors to the mountainous areas.
The region is home to 30 ethnic groups with a rich and diverse culture, magnificent landscapes and "golden destinations" like the Mai Chau Valley, the Moc Chau Highlands, the Dong Van Karst Park, the terraced fields of Mu Cang Chai, the historic base in Muong Phang Forest (from where General Vo Nguyen Giap directed the Dien Bien Phu Campaign against the French) and Mt Fansipan.
"We are building roads and extending the electricity network. We are developing our human resources and maintaining our traditions. We have designed tours with different themes, like the soul-searching tours upstream Red and Black rivers, community tours where you live like a local, adventure tours to conquer mountains, tours to see beautiful, rare flowers, and market fair tours where you meet people who come to buy and sell tools, maize, cattle and poultry, maize liquor and indigo fabric, and tours to explore all the dimensions of our vast terraced fields," explains Dang Xuan Phong, chairman of the Lao Cai People's Committee.
New stamps have been issued to mark the year.
One stamp carries the terraced fields and another the Mt Fansipan.
Broadcast live on national television, the ceremony gathered more than 100 performers, dancers and singers who highlighted the diverse cultures and colours of the region.
An active traveller since her student days, Cao Huong twice climbed Mt Fansipan in her youth and recalls how she used to climb steps everyday to prepare to scale the peaks.
"Fansipan has become accessible by cable car, but there are other mountains you can still climb with your feet and hands, and, in some cases, with the help of ropes, steel hooks and a porter," she says.
Vietnam's fourth highest peak, Bach Moc Luong Tu on the Hoang Lien Son Range stands tall at 3,040m above sea level.
Huong says it took her three days and two nights to get there. "In total, it's only 30 kilometres, but there are many dangerous slopes.
There was a cliff that we had to boulder and belay with the help of two porters who carried rice and other amenities for the group."
In the first three days of the Lunar New Year holiday, a record 40,000 people visited Sa Pa, 5,000 of them foreigners.
"We expect to receive 3.1 million tourists this year," said Ha Van Thang, head of the Lao Cai Culture, Sport and Tourism Department.
"About one million of the tourists would be foreigners," he added.
More visitors mean more income and job opportunities for local businesses.
But while tourism generates greater revenues for localities and their populations, some of the lasting negative impacts cannot be ignored.
The most obvious downside of tourism is environmental pollution.
"There's loads of plastic garbage along the road up to Mt Bach Moc Luong Tu, the fourth tallest mountain top of Vietnam," Huong laments.
"And that's despite the huge number of garbage bins".
She and her group bury organic garbage on roadsides and bring non-organic waste back with them.
"Self-decomposing toilets also need to be installed at the stops," she says.
According to some travellers, even at 2,000m above sea level, locals have cut down trees in protected forest areas to make huts and temporary shelters for overnight stays.
Forest fire is another risk.
"All tourists need to be warned of possible forest fires if they light fires in prohibited areas. Even locals and porters need training on this issue," Huong says.
An adverse social impact of tourism seen in the past several years is that children drop out of school to work for tourists.
Local administrations have taken the problem seriously, though, and convinced parents and students not to do this.
These days, children are no longer seen working during school time.
Some tourists have taken photographs of young people clad in ethnic Mong attire panhandling in downtown Sa Pa.
Several reports have spoken of rising prostitution.
"Any tourism campaign must ensure that locals, especially ethnic minorities, derive sustainable benefits that improve their standard of living and help them preserve their original traditions and lifestyles as much as possible," Huong says.