Temperatures are set to drop this week across southern and eastern regions of the South Island as a cold southerly should see temperatures about 5 degrees below average. Tomorrow the cold air moves into the far south and works its way up the eastern coastline and temperatures aren’t expected to rise very much at all during much of the week across much of Canterbury,Otago and Southland. “After the warmth of recent days it’ll be quite a contrast this week from Blenheim down to Invercargill with daytime temperatures almost halving as the cold winds move in” says weather analyst Richard Green. “Moist air will flow into the northeastern side of the alps as the winds swing in from the south but conditions are expected to brighten in the west after Tuesday” he says. Temperatures this afternoon have topped 20 degrees in a number of centers as the mild northerlies cover the country although damp conditions have spoilt a few outdoor activities for a few. According to NIWAs long range forecasts, milder than usual conditions are likely leading into summer with Auckland, Wellington and Christchurch seeing temperatures into the low 20s on a fairly frequent basis, if not a little higher and Dunedin in the high teens. La Nina is reforming causing the warmer than average conditions and is expected to last through late Spring and much of Summer and as a result rainfall totals could be a little lower than normal.