It is normal for the lake to fluctuate in winter and the level has seesawed above and below 277m a couple of times since March, when it was at 277.6m.
The lake also reached 277.1m at the end of July.
Lake Wanaka's long-term average for August is about 276.8m, but it never reached that at any stage last month.
The level steadily dropped from 276.7m throughout last month, with just one very slight rise in the middle of the month, according to the graphs on the Otago Regional Council's Water Information website.
Yesterday's severe weather warning from the MetService has forecast three days of heavy rain over the West Coast and Southern Alps.
Over 70mm of rain is expected east of the main divide, into the headwaters of the Otago and Canterbury lakes until midnight tonight.
Severe gale gusts were also expected early this morning in exposed inland areas of Otago and Southland.
