The Marlborough, New Zealand wine region is known for its bright sauvignon blancs. The region arrived on the international wine scene in 1985 when David Hohnen and Kevin Judd launched Cloudy Bay and their wines received rave reviews. The terrior of the region is the culture, geography, and climate that make a wine region unique. The Marlborough region’s climate is one aspect of its uniqueness.
Marlborough Wine Region Climate Data
The Marlborough Research Centre maintains weather stations in Blenheim and Awatere and both have relatively long histories. This post focuses on the data from the Blenheim station. The first published observation from the station was March 1st, 1996.
The data is available as one Excel file per year. I used an R script to sort through the different naming conventions to create one long consistent daily weather observation history for the Blenheim weather station.
Marlborough Wine Region Climate: Precipitation
The monthly average precipitation using the daily weather observations from 1986 to 2022 are shown below. The monthly averages range from approximately 75 mm to 120 mm, which makes is moderately dry. The graphic shows the lowest monthly rainfall and January is the driest month in Blenheim. The lowest rainfall in January is 0.4 mm, essentially no rainfall at all.
Marlborough Wine Region Climate: Temperatures
Monthly average temperatures at the Blenheim station in the Marlborough wine region are shown below. Wintertime temperatures in July average just above 10°C while summertime temperatures average just below 20°C. These temperatures are cooler than other regions such as Bordeaux, which averages approximately 22 °C, and Albemarle, Virginia in the USA, which averages approximately 25°C.
The graphic also depicts the maximum and minimum temperature recorded in each month over the 1986 to 2022 history. January daily temperatures have reached approximately 37°C.
Marlborough Wine Region Climate Change
Have temperatures at the Blenhiem station been increasing over time? To answer this we examine two pieces of data. The first is the warmest maximum temperature and the coldest minimum temperature recorded in each month of the history. We then used a linear regression against time to estimate if the data includes a trend or not. Interestingly, the trend of the monthly maximum of maximum temperatures is 0.0029 °C per month. Likewise, the trend of the minimum of the monthly minimums is 0.0023 °C degrees per month. Over the 25 year history of data the warmest monthly temperatures have increased almost 0.9°C and the coldest monthly temperature have increased 0.7°C.
Another analysis is to look at the percentage of days within each month greater than a certain threshold. The graphic below shows the percentage of days each month temperatures are greater than 25°C. While not tested statistically, visually, there is no dramatic increase in the percentages.
The Marlborough region is on the northern end of New Zealand’s south island. It is likely any temperature increases due to climate change are currently being ameliorated by the nearby ocean.
Conclusion
This post presents the climate of the Blenheim, NZ in the Marlborough Wine Region as measured by the Wine Research Center in Blenheim. The climate is frequently described as cool and the data bears that out. The data suggest that temperatures are increasing slightly as the impacts of climate change are likely being ameliorated by the nearby ocean.