International Winter Bike to Work Day was launched in Canada in 2013 as a friendly competition between cities and countries around the world. It takes place annually on the second Friday in February, the Union said.
Zagreb won the competition for three years in a row thanks to those who committed to cycling to work that day at least. Novi Sad, Serbia won last year's competition.
"Currently we are in third place and Varazdin is just behind," the Cyclists' Union said, adding that the people of the two cities did not need a special day to cycle to work, even in winter.
The Union invited citizens from all over Croatia to register at www.winterbiketoworkday.org and show that there are many who cycle irrespective of the weather.
This year the weather is extremely favourable, unlike the below zero temperatures in recent years, the Union said, adding that it would offer a cyclist's breakfast at a secret Zagreb location on Friday "as an incentive and a thank-you to those who leave cars at home, thus reducing the insufferable traffic jams and air pollution."