BANGKOK - The unusually long cold winter hitting Thailand in the past three months has killed at least 63 people, while temperature in capital Bangkok on Thursday fell to the lowest level in three decades.

"Bangkok hit its coldest record in 30 years Thursday morning when the temperature fell to 15.6 degree Celsius," Songkram Aksorn, deputy director general of the Thai Meteorological Department, was quoted by the Nation newspaper as saying.

Songkram said this year's cool season has been the longest for a decade, lasting almost three months. About 45 provinces across the country have been declared cold-spell disaster zones, with more than 25 million people affected.

The unusually long cool season, blamed on a cold front coming from the north, has also had an impact on Thailand's rice crop.

The new rice harvest coming in is not of good quality, because it has flowered too early with this cool season's unusually low temperatures, according to Vichai Sripraset, an honorary president of the Thai Rice Exporters Association.

"When temperatures are low, the fertilization is bad, and then you get a lot of empty rice husks," he added.