Although the spread of the disease has been contained since its outbreak in 2016, expected rainfall in the coming months could lead to a surge in cholera cases, according to the UN agency, Al Jazeera reported.
"The real problem is we're entering another phase of rainy seasons," WHO's deputy director for Emergency Preparedness and Response, Peter Salama, told reporters.
"Usually cholera cases increase corresponding to those rainy seasons. So we expect one surge in April, and another potential surge in August."
The disease spreads through water and food that has been consumed by a contaminated person and that is then passed on and shared with other people.
With a fatality rate of between 0.2 and 0.3 percent, the disease is widely considered to be preventable. Its manifestation is usually the result of poor sanitation and sewage infrastructure.
The ongoing conflict in Yemen has led to a significant degradation of the country's modest healthcare system.
"We're very concerned we're going to go from a failing health system to a failed one that's going to spawn more infectious diseases and more suffering," Salama said.
The number of cholera cases tipped over the one million mark in late December of last year and has killed more than 2,200 people.
The UN has also voiced concern over food shortages, which it says could lead to a famine if the conflict is not brought to an end.