Tensions between North Korea and the United States reached a boiling point this year, with President Donald Trump threatening to unleash “fire and fury” against Pyongyang and North Korean leader Kim Jong Un saying he would “surely and definitely tame the mentally deranged US dotard with fire.”

But North Korea hasn’t launched a missile since September 15, when a projectile flew over Japan and landed harmlessly in the ocean. US Special Envoy for North Korea Joseph Yun speculated that a testing break this long could be a sign that Pyongyang was ready to start negotiations over its nuclear program.

The problem is that focusing on this relative period of calm shifts attention away from a more troubling possibility: that North Korea may be preparing to launch missiles in early 2018 during the Olympics in neighboring South Korea.

“There would be no better time for North Korea to test a more fearsome three-stage intercontinental ballistic missile, big hydrogen bomb, or even try to launch a cyberattack on the Olympics themselves,” Harry Kazianis, an Asia security expert at the Center for the National Interest, told me.

He noted that Kim might be holding on to his arsenal to make a splash during the two-week event that will take place in Pyeongchang, South Korea — only 60 miles from the Korean border.

But experts say there are also mundane reasons why North Korea isn’t launching right now: The weather in North Korea is hostile during the winter, which makes it harder to test missiles, and North Korean troops are too busy harvesting food to eat.

All of this means North Korea’s decision not to launch any missiles in recent weeks isn’t a sign of a sudden change of heart in Pyongyang. Instead, it could be a sign that Kim is prepared to move closer to the brink of all-out confrontation with the US.

“This is all just the calm before the storm”

Many experts say bluntly that the current lull likely won’t last.

“If North Korea follows the usual cycle, I'd expect testing to pick back up again next year,” Sheena Greitens, a North Korea expert at the University of Missouri, told me.

Here’s what she means by that: North Korea usually stops testing around September, as the James Martin Center for Nonproliferation Studies chart below shows.

But in February 2018, the world’s best athletes will be in Pyeongchang. That may be too good an opportunity to showcase North Korean prowess for Kim to pass up.

“If I was a betting man, I would tell anyone who watches North Korea for a living to make sure their calendar is open from February 5 to 22,” Kazianis told me, referring to the competition’s dates. “This is all just the calm before the storm.”

It’s worth noting that North Korea could still launch a missile this year. On November 20, President Donald Trump put North Korea back on the state sponsors of terrorism list — which slaps even more sanctions on the country — and Pyongyang may want to respond quickly and forcefully.

But if history is a guide, there are reasons to believe North Korea may not test a weapon again in 2017.

North Korea has other priorities right now

Missile launches require good weather. Even NASA delays rocket launches sometimes because of storms.

That poses a problem for North Korea, which suffers from brutally cold and blustery winter weather. The country is sometimes called the “frozen land,” and the temperature can drop well below zero. Its capital city, Pyongyang, sees an average of 37 snowfall days per year. It’s therefore pretty hard to plan a missile launch when conditions are so poor.

At the same time, North Korea’s harvest season takes place during the last three months of the year. Instead of preparing missile launches, North Korean troops travel to rural areas to perform mundane agricultural chores, according to Jeffrey Lewis, an expert on North Korea’s missile program at the Middlebury Institute of International Studies.

And distributing harvested crops around the country doesn’t just require manpower. It also requires fuel — the same fuel Pyongyang would use to propel its missiles. But North Korea has a limited supply of it, and the amount is likely dwindling because of harsh sanctions slapped on the country by the US, China, and Europe. So come wintertime, Pyongyang prioritizes food transportation over missile launches.

Many of North Korea’s 25 million citizens are starving, and the poor weather conditions exacerbate that problem. North Koreans usually eat about 1,640 calories each day, while US health officials recommend consuming around 2,000 per day.

“Life is little more than a daily struggle to find enough food to stay alive,” Alf Evans, a British aid worker who spent time in rural North Korea, told the Telegraph in 2013. “Every scrap of earth that can be used to grow something is being used.”

There may also be a third reason for the lack of recent missile tests: The North Korean military usually trains in the winter, Van Jackson, an Asia security expert at Victoria University of Wellington, told Bloomberg. Preparations for the exercises require resources like fuel and money, which means there are fewer of each to launch missiles. The drills usually begin in December and sometimes continue into April.

So all signs for now point to a quieter end of the year. That means it’s worth enjoying the break in the action — because it may soon get much worse.