Press Release June 2018

Weather Data summary for June 2018 for the Blenheim Meteorological station located at the Grovetown Park campus of the Marlborough Research Centre.

June 2018 mean temperature and sunshine hours were close to average. June recorded 13 ground frosts and five air frosts. Rainfall and wind-run were well below average.

Table 1: Weekly temperatures, rainfall, sunshine and frosts recorded in Blenheim during June 2018
Mean Max Mean Min Mean. Diff. Rainfall
(mm) Sunshine
(hours) Total Ground Frosts Total Air Frosts
1-7 June 12.7 4.4 8.5 -0.2 3.6 18.4 2 1
8-14 June 14.2 5.7 10.0 +1.3 14.0 32.1 2 0
15-21 June 13.7 4.4 9.1 +0.3 21.8 32.6 1 0
22-28 June 13.3 1.4 7.4 -1.3 0.0 50.3 6 3
29-30 June 13.9 0.0 6.9 -1.8 0.0 17.5 2 1

1-30 June 13.5 3.7 8.6 -0.1 39.4 150.9 13 5
1986-2016 13.8 3.5 8.7 67.3 151.4 12.0 5.1

150.9 hours sunshine for June was 99.7% of the long term average of 151.4 hours (1986-2017)
June 2017 recorded 162.7 hours sunshine
June 2016 recorded 153.4 hours sunshine

The first three weeks of June were generally fairly overcast with only 83.1 hours sunshine recorded, or an average of 3.96 hours per day. The long term average daily sunshine for June is 5.05 hours. However, the final nine days of June recorded fairly clear skies and 67.8 hours sunshine or 7.53 hours per day.

Total sunshine for the first six months of 2018 was 1218.4 hours; 18.3 hours below the long-term average (1236.7 hours).

The news on the sunshine race between Blenheim and Richmond for 2018 is not so good. At the end of May Blenheim was only 1.5 hours behind Richmond. However, Richmond managed to record 22.5 hours more sunshine than Blenheim during June, so Richmond is now 24 hours ahead of Blenheim (Seems like Richmond managed to add an extra day to June).

June’s mean temperature of 8.6°C was 0.1°C below the long-term average temperature of 8.7°C (1986-2017).
June 2017 mean temperature was 8.8°C
June 2016 mean temperature was 10.1°C

The average daily maximum temperature of 13.5°C was 0.3°C below average
The average daily minimum temperature of 3.7°C was 0.2°C above average

Ground and Air Frosts for June (a ground frost is recorded at a height of 2.5 cm above a mown grass surface. An air frost is recorded in a Stevenson Screen at a height of 1.5 m). A ground frost is any temperature less than or equal to -1.0°C. An air frost is any temperature below 0°C.

Ground Frosts Air Frosts
June 2018 = 13 5
June 2017 = 10 1
June 2016 = 10 1

The coldest ground frost in June 2018 was -5.0°C recorded on 7th June. The air frost on the 7th was -0.7°C.
However, the coldest morning of June 2018 was actually the 23rd, with a ground frost of -4.7°C and an air frost of -1.3°C.
The coldest morning in June 2017 was the 15th with a ground frost of -4.6°C and an air frost of -1.4°C.
The average number of ground frosts for June is 12.0 and air frosts is 5.1 (1986-2017). So June 2018 was very close to the long-term average.

Mean temperature for the 12-months July 2017 to June 2018
The 11 months from July 2017 to May 2018 were all above average in Blenheim. June slightly spoiled the 12 month period coming in slightly below average (Figure 1). However, the mean temperature for the 12-months July 2017 to June 2018 was 14.01°C. This is the warmest July to June on record for the 86 years 1932-33 to 2017-18.

Figure 1: Blenheim mean temperatures for the 12 months July 2017 to June 2018 compared to the long-term average

Total rainfall in June of 39.4 mm was 59% of the long-term average (1986-2017) for June of 67.3 mm.
June 2017 rainfall was 18.4 mm.
June 2016 rainfall was 76.8 mm.
June 2015 rainfall was 87.0 mm.

Total rainfall for the six months January to June 2018 is 492.2 mm, 162% of the long-term average.

Rainfall for the 12 months July 2017 to June 2018
Monthly rainfall over the 12 months July 2017 to June 2018 has been highly variable. Four of the 12 months recorded well below average rainfall as indicated in Figure 2 (October, November, December and June). Three months recorded well above average rainfall (January, February and May). Five months recorded close to average rainfall (July, August, September, March and April).

Figure 2: Monthly and cumulative rainfall in Blenheim for the 12-months July 2017 to June 2018 compared to the long term average

Total rainfall for the 12 months July 2017 to June 2018 was 740.6 mm. This is 116% of the long-term average (636.0 mm).
July 2016 to June 2017 = 608.6 mm (96% of LTA)
July 2015 to June 2016 = 491.2 mm (77% of LTA)
July 2014 to June 2015 = 347.4 mm (55% of LTA)

Rainfall in July, August and September 2017 was close to average. However, with low rainfall from October to December it looked as if Marlborough was heading into a summer drought. That was not to be as the skies opened in early January 2018, followed by February 2018 being the wettest on record, so it turned it into a very wet, but warm summer.

Average daily wind run for June 2018 was 209.5 km, with an average wind speed of 8.7 km/hr. Well below the long-term average wind-run for June of 224.5 km and wind speed of 9.4 km/hr (1996-2017).

Rob Agnew
Plant & Food Research / Marlborough Research Centre

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Filed under Blenheim Weather Data, Weather Press Releases.

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