Only three players in the 57-man field finished play, which will resume Saturday. Showers are expected through Sunday at the $5.37 million season finale. Twelve golfers were unable to tee off.
Soren Kjeldsen of Denmark, who leads Spains Sergio Garcia by three shots at 6 under, had yet to start his round on a cold, wet, windy day at Valderrama.
Harrington, British Open and PGA Championship winner, was at par after 14 holes to stay six shots behind Lee Westwood and two behind money leader Robert Karlsson.
Harrington was at 5 over after 32 holes while Order of Merit long shot Miguel Angel Jimenez had a poor start to the second round and was at 7 over after four holes to fall 15 shots behind Kjeldsen. Karlsson was at 1 over after four holes.
I think we should not have played, Jimenez said. The conditions were brutal when we stopped playing. It might be unfair that todays round has not been canceled as we may not all be playing under the same conditions tomorrow, and conditions must be the same for everybody.
This is the 21st and final edition of the European Tours season-ending event, which will switch to Dubai beginning in 2009.
Officials said Valderramas fast-draining course allowed the field to start Friday, but the damage was done when two weather fronts hung over the Spanish coast rather than moving past as expected.
This is a very, very difficult course as weve seen over the years, and its not designed to be played in a sort of 25 miles-per-hour wind with lashing rain. It was a very brutal day, European Tour director of operations David Garland said. (But) I would say that the golf course was playable this morning,
Harrington can win his second Order of Merit title in three years with a victory, as long as Karlsson finishing no higher than third. A runner-up spot would be enough for Harrington if Karlsson is sixth or worse.
Westwood needs a victory with Karlsson outside the top three to take his second Order of Merit title and first in eight years.
Karlsson can become the first Swede to win the Harry Vardon trophy. He dropped a shot at the par-5 fourth for the second straight day and was 3 over before his day ended.
Jimenez needs victory to have any chance in the four-way race.
Defending champion Justin Rose pulled out after shooting an 81 for a two-day total of 19-over 161. The Englishman, last years Order of Merit winner, flew to South Africa to be with his family following the death of his grandfather.