BRUSSELS, Aug 23 (Reuters) - Euro zone consumer confidence fell markedly again in August, the European Commission said on Wednesday releasing its monthly indicator, in a new sign of weaker morale after the June 23 British vote to leave the European Union.

The Commission's flash estimate, which defied economists' forecasts of a rebound in confidence this month, showed euro zone consumer morale decreased by 0.6 to -8.5 in August from an unrevised -7.9 in July.

That took its total decline since the British referendum two months ago to 1.3 points.

Economists polled by Reuters had forecast that consumer confidence should rebound this month, to -7.6.

The marked drops over the summer followed a slight fall in June and two consecutive rises in April and May.

The figures for the European Union as a whole showed a much more stable situation, with the EU indicator edging down 0.1 to -7.8 from a revised -7.7 in July. The previous estimate for July had been -7.6. The stability in August came after a very sharp drop of 1.9 points in July.

(Reporting by Alastair Macdonald; Editing by Gabriela Baczynska)