A severe weather watch is in place for the headwaters of the Otago lakes and rivers, despite temperatures in the region forecast to be in the mid-20s for most of the week.
MetService has issued the watch for the possibility of more than 100mm of rain falling from this afternoon until Tuesday evening, about 10km east of the main divide with the possibility of "heavy rain'' spreading further east.
The watch comes on the back of a strong, moist north-westerly flow covering the South Island.
Meteorologist Rob Kerr said the east was looking dry, but "significant amounts of rain'' would fall in western parts.
Dunedin city was expected to reach a high of 24degC today, with similar temperatures tomorrow and Wednesday, and would peak for the week on Thursday with 25degC.
Oamaru was forecast to hit 24degC today, while Alexandra could expect a high of 23degC, Queenstown 21degC and Balclutha 19degC.
Temperatures would be much the same for the rest of the week, MetService said.
