MET REPORT Table 1: Blenheim Weather Data – August 2020
Temperature Blenheim recorded a mean temperature of 10.3°C during August 2020, 1.2°C above the long-term average (LTA). The first and fourth weeks of August 2020 both recorded well above average temperatures whereas the second and third weeks both recorded slightly below average mean temperatures (Table 2). However, the final three days of the month were exceptionally warm, with a mean temperature of 15.1°C; 6.0°C above the August LTA. To put the mean temperature of 15.1°C over the final three days of August into context, this is warmer than the LTA mean temperature for November of 14.8°C.
August August August Period August 2020 2020 LTA of LTA 2019 compared to LTA GDD’s for month -Max/Min¹ 34.8 183% 19.0 (1996-2019) 11.7 GDD’s for month – Mean² 52.1 146% 35.8 (1996-2019) 34.8 Growing Degree Days Total Jul – Aug 20 – Max/Min 45.3 159% 28.5 (1996-2019) 29.6 Jul - Aug 20 – Mean 78.4 132% 59.6 (1996-2019) 71.3 Mean Maximum (°C) 15.8 +1.6°C 14.2 (1986-2019) 14.5 Mean Minimum (°C) 4.7 +0.8°C 3.9 (1986-2019) 3.0 Mean Temp (°C) 10.3 +1.2°C 9.1 (1986-2019) 8.8 Grass Frosts (<= -1.0°C) 6 4.3 less 10.3 (1986-2019) 13 Air Frosts (0.0°C) 1 2.7 less 3.7 (1986-2019) 3 Sunshine hours 222.9 121% 184.7 (1986-2019) 221.9 Sunshine hours – lowest 129.2 1941 Sunshine hours – highest 235.0 2011 Sunshine hours total – 2020 1681.6 106% 1588.7 (1986-2019) 1788 Rainfall (mm) 49.6 80% 61.9 (1986-2019) 56.6 Rainfall (mm) – lowest 4.6 1969 Rainfall (mm) – highest 172.1 1990 Rainfall total (mm) -2020 269.8 62% 433.8 (1986-2019) 435.8 Evapotranspiration – mm 60.3 123% 49.2 (1996-2019) 57.2 Windrun (km) 207.8 89% 233.2 (1996-2019) 243.4 Mean soil temp – 10cm 7.7 +1.1°C 6.6 (1986-2019) 5.7 Mean soil temp – 30cm 9.6 +1.1°C 8.5 1986-2019) 8.0 1
Highest ever August maximum temperatures recorded two days in a row The 30th August recorded a maximum temperature of 21.7°C. This surpassed the previous highest ever August maximum temperature of 21.6°C recorded on 31st August 2006. However, 30th August only held the record for one day as the 31st August recorded a maximum temperature of 23.8°C. The 31st August 2020 is now the warmest August day on
¹GDD’s Max/Min are calculated from absolute daily maximum and minimum temperatures ²GDD’s Mean are calculated from average hourly temperatures
Table 2: Weekly weather data during August 2020 Mean Mean Max (°C) Min (°C) 1st - 7th 16.7 6.1 8th - 14th 14.7 3.1 15th - 21st 14.0 3.0 22nd - 28th 15.5 5.1 29th – 31st (3 days) 21.6 8.6 1st – 31st 15.8 4.7 August 2020 (+1.6) (+0.8) August LTA (1986 – 2019) 14.2 3.9 LTA – Long Term Average
6 / Winepress September 2020
Mean (°C) Deviation 11.4 (+2.3) 8.9 (-0.2) 8.5 (-0.6) 10.3 (+1.2)
Ground Air Frosts Frosts
Rainfal Sunshine (mm) (hours)
0 2 3 1
5.4 0.0 22.0 22.2
37.3 57.2 49.8 50.1
15.1 (+6.0) 0 0 10.3 6 1 (+1.2)
0.0 49.6 (80%)
28.5 222.9 (121%)
9.1
61.9
184.7
10.3
0 0 1 0
3.7
