UPDATE 2-Brazil again boosts real as it notches weakest year since 2020

Adds closing rate, year-to-date figures in paragraphs 1-3, finance minister comment in paragraphs 4-5

SAO PAULO, Dec 30 (Reuters) - Brazil's central bank sold another $1.815 billion in a Monday spot auction, partially containing the real currency's losses, which closed the year at its weakest level against the U.S. dollar in four years.

For the year, the Brazilian real depreciated by more than 27%, its biggest swing since 2020 when it weakened 29% versus the dollar.

The real BRBY closed Monday's session up slightly, gaining 0.2% to trade at 6.179 reais per greenback.

Finance Minister Fernando Haddad cheered the monetary authority's bid to strengthen the real through spot auctions later on Monday, and pointed to the U.S. currency's strength as the major culprit.

"The exchange rate (in Brazil) is not fixed. The dollar closed strong worldwide," the finance chief told reporters in the capital Brasilia.

The latest dollar auction was called right after the real fell to 6.24 reais per U.S. dollar, or down 0.7%.

So far this month, the central bank has sold nearly $22 billion in spot auctions, in addition to another $11 billion in repurchase deals, as the real sank to historic lows amid market worries over government spending as well as currency outflows.

After Monday's auction, the currency rose by some 0.3%.

(Reporting by Isabel Teles and Victor Borges; Editing by David Alire Garcia and Aurora Ellis)

((Isabel.Teles@thomsonreuters.com;))