Consumer sentiment in South Korea improved for the first time in four months in January despite the central bank's sharp downward revision of this year's growth forecast, data showed Tuesday.

The overall consumer sentiment index (CSI) reached 102 in January, inching up from a revised 101 in the previous month, according to the Bank of Korea (BOK). A reading above 100 means that optimists outnumber pessimists.

The reading for December was revised due to an annual standardization process. The central bank resets the benchmark 100 level by averaging the monthly figures posted in 2003-2014.

The result comes as a surprise, given that the central bank on Jan. 15 slashed its growth outlook for Asia's fourth-largest economy to 3.4 percent from 3.8 percent, citing lackluster growth in the fourth quarter stemming from "external" factors such as the tightened mobile subsidy law.

"It seems that ongoing policy efforts helped shore up sentiment. There is also a general trend in which a rebound occurs after three or four consecutive months of decline," said a central bank official.

The index measuring households' perception of the economy improved to 74 from 41. Their six-month outlook on the economy also rose to 90 from 85.

Other readings also improved from the previous month, with their outlook on the job market reaching 86, up from 83 a month earlier.

Consumers' inflation forecast for the next 1-year period came in at 2.6 percent, staying on par from the previous month. The reading is below the central bank's 2.5-3.5 percent target band for the years 2013-2015.

In its recent outlook revision, the central bank lowered its inflation outlook to 1.9 percent from 2.4 percent, citing a plunge in global oil prices.

The CSI survey of 2,200 households across the nation was conducted from Jan. 13-20. (Yonhap)