A period of spring-like weather at the Games has been followed by cloud and rain, a far bigger headache than warm sunshine — even though organisers remain unruffled.

The biathlon event has been the worst affected so far, having already been postponed from its original start time of Sunday evening.

The event has now been rescheduled for 3:30 pm (1130 GMT) on Monday.

It means Norwegian star Ole Einar Bjoerndalen will have to wait longer for his bid for a record 13th Winter Olympics medal and France’s Martin Fourcade will have to kick his heels as he seeks a third gold at Sochi.

Coaches at the Laura biathlon course said the biggest problem at the moment was not so much the fog as the poor quality of the snow.

“The problem is not really the fog, it’s the state of the track,” Siegfried Mazet, the French team’s biathlon shooting coach said. “The snow cover is too wet.”

At the Extreme Park, where snowboard and freestyle skiing are taking place, the weather has played havoc with training schedules, but until Monday had not affected the competition.

An official International Ski Federation (FIS) statement said: “Due to fog, the seeding phase of the men’s snowboard cross is cancelled.

“The athletes will be seeded to the 1/8 finals based on the FIS rank in the current FIS points list.”

The start time for the last 16, where riders race in heats of up to six people, remains 1:30 pm (0930 GMT).

On Friday, warm weather forced women’s ski cross and ski halfpipe training sessions to be called off while a men’s aerials training session was pushed back.

With temperatures reaching 15 degrees Celsius (59 degrees Fahrenheit),the courses had become unstable.

But International Olympic Committee Mark Adams remained sanguine, saying: “No event has been cancelled so far.”