August 2006 Colder, Wetter, Windier

Tawa’s climate during August 2006 was colder, wetter and windier than last year, continuing the trend set during July.

Automatic and manual readings taken at Tawa since 2003 can be summarised as follows:

The lowest August temperatures were 0 °C (2003), -1 °C (2004), 1 °C (2005) and -1 °C (2006).
The average daily low temperatures were 6 °C (2003), 6 °C (2004), 7 °C (2005) and 6 °C (2006).
The highest August temperatures were 16 °C (2003), 15 °C (2004), 17 °C (2005) and 16 °C (2006).
The average daily high temperatures were 13 °C (2003), 12 °C (2004), 14 °C (2005) and 12 °C (2006).

Average temperature: 10.6 °C (2005), 9.5 °C(2006).
Average humidity: 86% (2005), 86% (2006)

Days with frost: 2 (2003), 3 (2004), 2 (2005) 3 (2006).
Days with rain: 16 (2003), 19 (2004), 9 (2005), 16 (2006).
Days with thunderstorms: none (2003), none (2004), none (2005), 1 (2006).
Days with hail: none (2003), 4 (2004), none (2005), none (2006).
Days with strong winds: no data (2003), 6 (2004), 4 (2005), 11 (2006).
Rainfall: 22 mm (2005), 156 mm (2006).

Weather notes show that August 2003 was a typical end-of-winter month with drizzly days and occasional days of steady rain. Ground frost was noted on the 5th and the 18th.

August 2004 started with ground frosts being recorded on the 1st and 3rd and frost being noted on the trees on the 4th before drizzly conditions set in. The sun broke through on the 8th, but steady rain returned the following day, easing on the 11th. A north-west gale arose on the 13th, with winds rising to severe gale on the 15th, easing later in the day. A southerly change brought hail on the 16th, with wind rising to gale force on the 17th, accompanied by sleet, hail and icy showers. The wet and windy conditions eased early on the 19th. Calmer conditions applied until the 28th when more hail and icy showers were experienced. The month ended with a cold, foggy start to the 31st.

August 2005 was noticeably warmer and calmer than the previous year. Drizzle on the 1st was followed by cooler sunny days, and we narrowly avoided frosts on the 3rd, 4th and 6th with overnight lows of 2 or 3 °C. Two local earthquakes of magnitude 3.5 on the 5th diverted attention from the weather, until drizzly conditions returned on the 8th. Periods of steady rain alternated with dry and cloudy conditions until the 13th when we experienced two days of gusty nor’westers. Still conditions on the 15th allowed a ground frost to set and a gusty northerly on the 17th heralded steady rain the following day.

Cold, damp and breezy days followed until the 21st. Light rain fell on the 23rd, and drizzle on the 24th, followed by a couple of fine days. Steady rain on the 27th was followed by the second frosty morning of the month on the 28th.

August 2006 commenced with the ground already carrying a water burden from July rains, and set the tone for a winter of landslips in the Wellington region. Misty conditions on the 1st deteriorated to serve up fog, low cloud, showers then drizzle on the 2nd. Steady rain on the morning of the 3rd gave way to cooler sunny days which lasted until steady rain returned on the 6th. 17 mm of rain was recorded in Tawa, but conditions were much worse in Northland (north of Auckland, not the Wellington suburb) where flooding caused disruption, and the Bay of Plenty recorded heavy rain with 80 mm being recorded in Te Puke on the 6th.

The steady rain continued on the 7th, with 21 mm being recorded in Tawa while the Bay of Plenty and East Cape areas experienced surface flooding and road closures. Rainfall at Tawa eased back to 8 mm on the 8th under the influence of a southerly gale, with conditions easing the following day. A strong nor’wester on the 12th was followed by a chilly strong southerly which brought more rain on the 14th.

Showers continued until late on the 15th, and a ground frost was recorded the following morning. Pleasant sunny days allowed the ground to start drying out, and the gusty northerlies of the 19th were welcomed for their ability to help things to dry out. A brief thunderstorm on the 21st, was followed by frosty mornings on the 23rd and 24th.

Showers on the 25th led into the next heavy rain event when a strong nor’wester delivered 32 mm of rain to Tawa in the 12 hours to midday on the 26th. Slips in the Aro Valley and Wellington caused 4 houses to be evacuated, the Hutt River rose abruptly and the Wellington-Johnsonville commuter railway was closed when a unit was derailed by a slip. Later in the day, slips were reported in Ngaio and several roads, including State Highway 1 at Paekakariki were closed. By the end of the day, Tawa had recorded 43 mm of rain.

Residents began hoping that this was winter’s last gasp with dry conditions applying until the end of the month with gusty northerlies helping to dry out sodden soils on the 28th, 30th and 31st.

Following the mild winter of 2005, this last winter has been cooler, wetter and windier. However, the climate summary issued by the National Institute for Water and Atmospheric Research (NIWA) shows that while most of the Wellington region experienced rainfall 150% higher than average, the sunshine hours were 120% higher than average and temperatures about average during the winter of 2006.

Leave a Reply