For the month as whole, September mean sea level pressure was lower than normal over and to the northeast of the North Island and higher than normal over and to the west of the South Island, resulting in more southeasterly winds than normal over the country.
Temperature
Near average temperatures (i.e. -0.50 to +0.50°C of the September average) were experienced across most of the country while limited areas in the Far North as well as coastal parts of Canterbury and Marlborough observed below average temperatures (i.e. -0.51 to -1.20°C of the September average).
Rainfall
Rainfall during September was above normal (i.e. 120-149% of normal) to well above normal (i.e. >149% of normal) for eastern parts of the North Island as well as Otago, Banks Peninsula, and much of Southland. In contrast, most of the remaining locations throughout the country experienced below normal (50-79% of normal) or well below normal (<50% of normal) rainfall levels except for parts of Northland and Wellington which experienced near normal rainfall totals.
Soil Moisture
As of 1 October 2018, soil moisture levels were above normal for the time of year for much of Otago, particularly toward the coast, as well as around coastal Gisborne. Drier than normal soil moistures were present from Nelson through to northern Canterbury and through much of the central and southern North Island. Soil moisture levels were generally near normal for the time of year across the rest of the country.
