Central Otago Weather Summary

Winter 2010

Countdown to budburst (see annual cycle)

Weather June
June was cold and dull, especially in areas where cloud cover lingered throughout the day. An inversion layer over the last week failed to lift in many areas resulting in daily temperatures barely rising above freezing. The average daily temperature was 2.8 C with temperatures dropping below freezing most nights. The majority of wind (average wind speed 4.2 km/hr) was recorded prior to and during the three rain events, and the first snow (22 June) fell in Wanaka on the day after the winter solstice. The total rainfall for the month was a solid 70mm.

May
The average daily temperature for May was 7.4 C. This was largely propped up by the first two weeks during which the average temperature was 9 C and afternoon temperatures above 15 C on most days. Temperatures progressively dropped over the second half of the month with the last week recording an average of 5.3 C. The average wind speed for the month was slightly below April at 6.1 km/hr and the total rainfall 43 mm, most of which fell at the end of the month. Heavy rain was recorded in North Otago during this time. Six moderate (all above -3 C) frosts were recorded over the month and overall, the month was mild, bringing a gentle close to the growing season.

Autumn 2010

April
The temperatures during April were slightly warmer than normal (average daily temperature 12.4 C) with 78 GGD’s recorded compared to an average of 53. The average wind speed for the month was slightly above average (average 6.9 km/hr) with most of this associated with heavy rains falling between the 24th and 29th. April was relatively frost free, however early frosts on the 7th and 8th put the region on alert over the harvest period.

March
March was a good ripening month with temperatures well above average. The daily average temperature was 15.6 C and 170 GGD’s were recorded compared to a long term average 140. Very little rain fell during the month and young planting began to feel the pinch of an extended dry period. A small amount (20mm) of rain falling between the 22nd and 24th was very welcome. No damaging frosts were recorded during the month.

Summer 2010

February
February was a great growing month. The first three weeks were hot, dry and still and the last week saw overcast skies and more wind, with temperatures remaining high. The mean daily temperature was 19.4 C and 263 GDD’s were recorded; 65 above the long term average. Irrigation was required in most vineyards with a meagre 12 mm falling on the 13th and 18th. The first half of the month was calm with an average wind speed of 4.7 km/hr. This only rose to 5.9 km/hr as wind speeds increased over the second half of the month.

January
Overall January was mild, wetter and stiller than average with fine weather over the last week greatly appreciated by viticulturists and holidaymakers alike. The mean daily temperature (17.2 C) was slightly cooler than average, largely due to inclement weather over the first two weeks in which 68 mm of rain fell (double the average for the month). A freak hailstorm on the 11th caused alarm for some growers. While most of the wind occurred during the first two weeks calmer conditions over the rest of the month resulted in a low overall wind speed of 7.7 km/hr. Fine weather over the last week lifted the GDD’s to a respectable 222 GGD’s, slightly down on a 240 average.

Spring 2009

December
The weather during December was temperate and moderately unstable with a series of cyclones passing below the country. The average daily temperature was 15.9 C with 182 GDD's recorded for the month (186 GDD’s average for December). After a dry November, a welcome 37 mm of rain fell on the 9th with light falls on five other occasions making a total of 41mm. The wind speed was slightly above average (10.5 km/hr compared to 10.2 average) and after a surprising dip below freezing on the morning of the 21st, overnight temperatures typically remained above 5 C.

November
The weather during November was dry, overcast and windy. Only 5 mm of rain fell during month and the daily average temperature rose from 9.3 C in October to 14.2 C, recording a solid 127 GDD’s for the month. The average wind speed was above average at 13.2 km/hr and besides a light frost on the 17th, November was largely frost free.

October
The weather during October was still, overcast and cool. The average wind speed was very low at 8.9 km/hr (typically over 12.0 km/hr) and the daily average temperature was 9.3 C (only 20 GDD's - half the normal). There were two frost events (-2 C on the 5th and -0.5 C on the 30th) and 32 mm of rain fell over the month.

Winter 2009

September
The weather during September was blustery (especially during the middle of the month) cloudy but dry. The average daily temperature rose steadily for the first half of the month. Blustery conditions on the 14th were accompanied by an afternoon temperature topping 20 C. Three frontal systems brought rain at the beginning, middle (14th) and end of the month recording a modest 22 mm. The average monthly wind speed rose to 10.6 km/hour (slightly below average) and the daily average temperature was 8.4 C. Ground temperature rose from 6.1 C in August to 8.0 C and six mild frosts were recorded at the beginning (4) and end (2) of the month.

August
The weather during August was warm, windy and wet. The average daily temperature increased dramatically from 2.8 C in July to 7.4 C, and the ground temperature from 2.5 C to 6.1 C. The average wind speed rose to 9.4 km/hour (slightly above average) with most of this recorded just prior to eight rain events; totalling 83 mm for the month.

July
The weather during July was cold and dull. Snow was recorded in Wanaka on the 2nd and was followed by two weeks very cold conditions. Following wind and rain at the beginning of the third week, temperatures rose from an average of 0 C (first two weeks) to a daily average of 5 C (for the second two weeks), resulting in the average for the month of 2.8 C. The average wind speed for the month was 6.7 km/hour with most of this recorded in the second fortnight.

June
The weather during June was very cold, dry and still. Overnight temperatures dropped below -5 C on 10 of the 30 days. Very little wind meant cloud cover remained well into the afternoons and on occasion persisted over many days. Wet and overcast conditions between the 10th and 14th resulted in 10mm rain (the only rain during the month). An extended period of freezing cloud cover kept temperatures constant at 0 C between the 21 st and the 29 th. The average daily temperature (1.5 C) and average wind speed (3.2 km/hour) were both very low when compared to other years.

May
The weather during May was dull, wet and cold. Still conditions did little to dissipate cloud cover and resulted in an average daily temperature of 4.6 C. Brief periods of blue skies were typically accompanied by strengthening winds with these winds heralding the coming of rain and further overcast conditions. The monthly rainfall was very high at 123 mm with 59mm falling during one event.

Autumn 2009

April
The temperatures during April were slightly warmer than normal (average daily temperature 11 C) with 70 GGD’s recorded compared to an average of 53. Freezing temperatures overnight brought the first frosts on the mornings of 9th and 10th and were followed by a series of hard frosts at the end of the third and beginning of the fourth weeks (20-24th). The average wind speed for the month (3.8 km/hr) was low (average 5.8 km/hr) and a solid 48 mm of rain fell over two events (6-9th and 25-29th).

March
Overall the weather for March was settled, with temperatures slightly lower than average (120 GGD’s compared to 140). Despite the mercury rising above 25 C on 10 afternoons, cool overnight temperatures resulted in an average daily temperature of only 12.8 C. The first week March was the warmest (average daily temperature 17 C) and the second, the coolest (average daily temperature 12 C). The average wind speed (4.4 km/hr) was low for this time of the year (average 7.0 km/hr). 16 mm of rain fell on four occasions (greatest 10 mm) and were preceded by strengthening winds and followed by cooler conditions. While no damaging frosts were recorded, temperatures threatened to go below freezing on the mornings of the 22nd and 23rd.

Summer 2009

February
February was wetter (49 mm) and cooler than average (160 GDD’s compared to an average of 210) with still conditions and lingering cloud. Despite a hot spell during the first few days of the second week (max. temp. 29 C) the average daily temperature for the month was only 15.7 C. A few warm days was followed by rain and cold weather during the middle of the month and again, a few warm days at the end of the month ended in heavy rain on the evening of the 28th. The average wind speed of 6.7 km/hr was significantly lower than January and the 5 rain events assuaged any thought of drought. Overall, and similar to last year, February failed to live up to it’s historical reputation of being hotter than January.

January
Overall January was slightly cooler than average (233 GGD’s compared to an average of 240), despite half a dozen very hot days. Average daily temperatures rose over the first fortnight before dropping again during the third week (daily average 12 C). A warm final week saw average daily temperatures rise back to around 20 C. Blustery conditions over the first week were followed by stable fine conditions during the second. Light but constant wind during the middle of the month was followed by still conditions at the end. Overall, the average wind speed of 10 km/hr was typical for January. No rain fell during the second half of the month (total rainfall of 40 mm for the month).

Spring 2008

December
Overall December was cool (average daily temperature 15.1 C and 160 GGD’s for month compared to 221 last year) and wet. Rain events occurred regularly every 4-5 days (with the exception of Christmas day) ranging between 2 and 51 mm. Total rain for the month was (112 mm) was over three times the December average and while the cool, wet conditions have had an adverse affect on flowering, the average wind speed for the month was significantly below average (8.4 km/hr compared to average of 10.1 km/hr).

November
Overall November was a good growing month with warm, dry and relatively stable conditions prevailing. While a major frost event was recorded on the 8th most growers were well prepared and damage was limited. Warm conditions (average daily temperature 13.8 C) produced a solid 130 heat units for the month (average for November 125 GGD’s). Soil temperature rose sharply from 11 C in October to above 15 C. Little rain fell over the month; however, a welcome anticyclone brought rain around the 24th. Continued dry conditions have necessitated irrigation in many areas.

October
The weather for October was mild, dry and relatively stable. Average daily temperature was up a degree and a half from September (10.5 C compared to 8.9 C in September) and average soil temperature is currently a little over 11 C. Little rain fell during the middle fortnight of the month and as windy conditions tend to precede rain events, the number of windy days was less. This was reflected in the average wind speed (12.4 km/hr compared to the average 13.4 km/hr for October). Six light frosts were recorded on the 9th, 19th, 22nd, 24th 26th and 30th have not been problematic with temperatures barely falling below freezing each time. As the shoots grow and their solute levels fall, the frost risk will increase.

Winter 2008

September
The weather overall for September was unsettled with 8 rain events recorded during the month. Cloud and wind moderated overnight temperatures with the only negative temperatures recorded on mornings of the 5, 6, 7 and 28th. Blustery conditions around the equinox (22nd) heralded the beginning of the spring winds. The average daily temperature for the month was 8.9 C and the average soil temperature rose from 4.5 C in August to 8.5 C [Queensberry].

August
Overall, August was a stable, cool month recording an average daily temperature of 4.0 C. The first 10 days were dominated by a large slow moving anticyclone. Cool mornings, cloudy/blue afternoons and little wind. Heavy frosts were recorded on the mornings of the 10th and 11th. A series of cyclones during the middle of the month brought rain and snow (at high altitudes) and generally cloudy, overcast conditions. Stable conditions between the 18 th and 21th (heavy frosts on the mornings of the 19th and 20th) were followed by strong winds heralding the arrival of a large cyclone centred over the North Island. Heavy rain recorded on the 22nd was followed by damp cloudy/conditions until the 26th. The remainder of the month, like the beginning, was dominated by a large slow-moving anticyclone. Cool/frosty mornings were followed by fine, blue afternoons with little wind. Average soil temperature for the month was 4.5 C.

July
Overall the month was damp and dull with an average daily temp of 3.2 C (compared to 2 C last year). The first half of the month dominated by two anticyclonic frontal systems (2-5th and 11-12th) bringing rain and snow at higher altitudes. Outside these events the weather was still and calm with the severity of morning frosts largely dependent on the amount of overnight cloud cover. A heavy frost was recorded on the 1st and minor frosts on the mornings from the 6th through to the 10th before the second front came through. While cloud cover moderated the severity of frosts, in some areas still conditions resulted in cloud lingering into the afternoons causing cold and dull conditions. The second half of the month was dominated by a series of cyclonic weather systems resulting damp overcast conditions. The first two systems (15th and 22nd) bringing rain followed by cold southerlies were followed by two large tropical storms (27th and 29th) that, while causing heavy rain and high winds in the upper North Island, had little impact in Central Otago where cloudy cool conditions prevailed. Average ground temperature for the month was 3.8 C

June
A mild month recording an average daily temperature 5.5 C, rising a degree and a half compared to May. Wind on the 6th was followed by wet weather between the 7th-9th before warming up (daily average 9 C) during the middle of the month. A second front brought a small amount of rain overnight on the 22nd. Mild/cloudy conditions for the remainder of the month was followed by a heavy frost on the morning of the 30th (-5 C).

May
The average daily temperature for May was 4.0 C, falling rapidly from 9.5 C recorded in April. Unlike the Indian summer conditions experienced last year (May 10.0 C) winter took hold quickly and while conditions were stable (cold, frosty mornings and fine, clear afternoons) for most of the month, two frontal systems passing through at the beginning and end of the month resulted in unstable conditions (wind and rain) with the second bringing 3 days of rain (22th - 24th). Overall the weather was stable with cold overnight temperatures.

Autumn 2008

April
The average daily temperature for April was 9.5 C, falling from 14 C in March and significantly cooler than this time last year (10.4 C).Two frost were recorded on the 20th and the 27th.

March
The average daily temperature for March was 14.0 C, falling from 16.7 C in February. Fine stable weather have resulted in 125 GGD's which have aided ripening and will make the 2008 season a "warm" year. Morning cloud and fog resulted in moisture retention in vineyards during the middle of the month. Cool mornings and warm afternoons at the end of the month will contribute to the quality of this harvest. Harvesting is underway in warmer sub regions.

Summer 2008

February
The average daily temperature for February was 16.8 C, falling from 18.7 C in January. While a sobering 190 GDDs were recorded, temperatures were not excessively low. Continued hot temperatures would have exacerbated already dry vineyard conditions and most likely resulted in vine water stress. Lower temperatures combined with a moderate rainfall have alleviated this, and while development has slowed slightly, the strong start to the season will ensure grapes get to full maturity. Overall, weather during February was mild and stable and 20% of the berries are through verasion.

January
Hot conditions (average daily temperature 18.5°C) especially during the first half of the month saw good growth. Little rain fell until the 22nd, with supplementary water required - especially on more gravelly soils. Overall January was a hot month.

Spring 2007

December
Warm conditions (average daily temperature 17 C) saw shoot growth increase, with flowering occuring around the 20th. Very little rain fell during the month and many vineyards began irrigating. Overall December was a good growing month

November
Two frost events occured during the month (9th and 28th). The frost on the 28th was unexpected by many growers and was what would be considered a "late frost". Warm conditions (average daily temperature 13.0 C) saw shoot growth increase, which was encouraging after the cool October. Very little rain fell during the month and many vineyards began irrigating. Overall November was a good growing month

October
Five frost events occurred during October and with budburst approximately 1-2 weeks late, the first three occurred before the buds had opened. As the young shoots began to immerge, frost protection was necessary on the mornings of the 27th and 28th with temperatures dropping below freezing just before dawn. Average daily temperature for October was 9.0 C compared to 8.5 C in September. The average ground temperature rose (now 10 C) from 8.5 C in September. Overall, weather during October was unsettled (winds strengthening prior to rain events), with still periods corresponding to frosts events.

Winter 2007

September
The average ground temperature for September was 8.5 C rising from low of 3.0 C two months ago (July). The buds are beginning to swell with budburst expected in the next two weeks. While the frost risk will decrease over the next two months, the damage associated with a frost event increases. A bad frost in late November can result in a month s growth being lost. Average daily temperature for September was 8.5 C compared to 5.5 C in August. 30mm of rain fell at the beginning of the month with a further 9mm on the 23rd, and 9mm on the 30th. Overall, September has been a good month, with no time lost to poor weather.

August
Ground temperatures are beginning to rise with the average for the month being 5.5 C compared to 3.0 C in July. Average daily temperature for August was 5.5 C compared to 2.0 C in July. The length of the days increased as the sun’s arc broadened across the sky. Crisp blue mornings and warm afternoons were common throughout the month, with winds building prior to rain events. A front came through on the 11th bringing 15 mm of rain with other rain events being minor. Overall, August has been a good month, with no time lost to poor weather.

July
Five days of overcast wet weather at the beginning of July was followed by two and a half weeks of very low temperatures. During this period the average the daily temperature was well below 0 C; with a -8.2 C recorded overnight on the eighth. This cold snap would have killed many of the mildew spores over-wintering in the vineyard. Temperatures rose again after rain on the 25 and 26th.

June
The Indian summer has come to an abrupt end with the May average temperature of 10 C dropping to 2.4 C in June. The first snow fell on the 21st June and was followed by a week cold weather (daily temperatures <5 C) which meant that the snow was still evident in shaded areas over a week later. The end of the month brought rain and overcast weather.

[Note - The Central Otago region is large and diverse with vineyards located from the valley floors (150 metres above sea level) to the lower terraces of mountain ranges (450 metres). The observations given here are from one vineyard and are only generally respresentative of the entire region]

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