January 2006 Much Windier Than Previous Three Years

Manual weather data has been collected at Tawa since 2003 and in 2005 it was augmented by the installation of an automatic weather station. This report blends the historical data from both sources to provide a 4-year climate overview.

The manual readings are obviously subjective, and represent the microclimate where the observations were made. The weather station is sheltered from the south owing to local topography. Manual data for January 2003 is incomplete.

Tawa’s climate during January 2006 was much windier but drier than the previous three years.

Readings taken at Tawa:
The lowest January temperatures were 7 (2003), 10 (2004), 8.2 (2005) and 8.2 (2006).
The average daily low temperatures were 13 (2003), 12 (2004), 11 (2005) and 13 (2006).
The highest January temperatures were 29 (2003), 28 (2004), 28.3 (2005) and 29.7 (2006).
The average daily high temperatures were 23 (2003), 19 (2004) 18 (2005) and 23 (2006).
Average temperature: 17.7°C (2005), 18.0°C(2006).
Average humidity: 80% (2005), 75% (2006)

Days with frost: no data (2003), none (2004), none (2005), none (2006).
Days with rain: no data (2003), 11 (2004), 10 (2005), 8 (2006).
Days with thunderstorms: no data (2003), none (2004), 1 (2005), none (2006).
Days with hail: no data (2003), none (2004), none (2005), none (2006).
Days with strong winds: no data (2003), 7 (2004), 5 (2005), 15 (2006).
Flood events: no data (2003) none (2004), 1 (2005), none (2006).
Rainfall: 99 mm (2005), 58 mm (2006).

A sudden storm event on the 8th and 9th of January 2004 brought strong winds from the northerly quarter, with gusts up to 120 km/h being recorded in the Wellington area. Later in the month, a southerly storm on the 20th and 21st brought a sudden downpour and temperatures plunged as low as 10°C.

In 2005 a storm on the 5th and 6th of January brought torrential rain, with 41 mm being recorded by the newly installed weather station on the 5th, with a maximum rain rate of 32 mm/hr at 8:55 p.m. By late morning, State Highway 1 had been washed out at McKay’s Crossing, and there was flooding at Otaihanga and in the Hutt Valley. Conditions eased until a powerful thunderstorm dumped another 40 mm at Tawa on the 8th, with the rain rate reaching 86 mm/hr at its peak. There was surface flooding at Tawa, Paekakariki and in the Hutt Valley. Both State Highways to the north were closed, and Wellington was isolated.

January 2006 was certainly windier than the three previous years, and gusts of 165 km/h were recorded at Mt. Kaukau, and 120 km/h in Wellington on the 3rd. A gust of 50 km/h was recorded at Tawa on the 5th. In all there were strong winds blowing on 15 days during the month.

Minor flooding resulted from a downpour on January 25th, 2006, when 32 mm of rain fell in Tawa, with the rain rate hitting 120 mm/hr at 2:29 p.m. Whilst traffic was disrupted, the event was short-lived and things returned to normal by late evening. In Wellington city storm drains backed up and there were reports of flash floodwaters up to 1 metre deep in a few places.

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