Harvest Climate: Temperature & Precipitation

September and October are the harvest months for winegrapes in the Okanagan Valley. Precipitation and temperature affect the quality and harvest time of the winegrapes. Harvest months that are too cool or warm can lead to unbalanced berries (for example, too warm can mean sugar to acid ratio that is too high).  Additionally, a rainy harvest season may dilute the winegrapes and decrease the overall quality of the yield and potentially cause issues with disease.

Both temperature and precipitation for September and October are in the following maps of the Okanagan Valley of British Columbia, Canada.

The maps below have three tabs, each shows the same information but allows you to visualize it in a slightly different way. 

    • One the first tab (Interactive) you can zoom in and out. Importantly you can see the warming scenarios by clicking on the small square showing three layers in the upper right corner of the map; for best viewing we recommend checking only one box at a time of the three options (Historical, Moderate warming, High warming). This box also lets you change the underlying map (basic topographic or  imagery, which gives satellite views).
    • The middle tab (Compare Warming Scenarios) shows the historical, moderate warming and high warming scenarios side-by-side for easy comparison.
    • The right tab (Anomalies) shows how much of a change occurs from the recent (historical) past versus the moderate (MW) and high (HW) warming scenarios. 

More information about these maps can be found below, here

Mean Minimum Daily Temperatures: September

Mean Minimum Daily Temperatures: October

Accumulated Precipitation: September

Accumulated Precipitation: October

More Information

Anomalies are a metric which highlight the change in a variable (minimum temperature, for example) from the recent historical average (1970 – 1989). Positive values indicate a projected increase from the past. For example, a value of -2 would mean temperatures will be two degrees cooler than the historical average, while a value of 2 would be two degrees warmer than the historical average. 

Warming Scenarios:
wo warming scenarios are represented in the data. The Moderate Warming (MW) and High Warming (HW) scenarios are represented by averaging the data for the periods of years between 2040 – 2059 and 2070 – 2089, respectively. These warming scenarios represent projected future climate based on a high emissions scenario at two timepoints in the future. For more information on the climate scenarios see, About.

Average Anomalies (Warming Scenario – Historical):

    • Mean Minimum Daily Temperature Anomalies:
      • September: the historical average temperature is 7.5 °C, with warming temperature rises:
        • Moderate Warming: 4.8 °C
        •  High Warming: 8.3 °C
      • October: the historical average temperature is 2.7 °C, with warming temperature rises:
        • Moderate Warming: 3.6 °C 
        • High Warming: 5.8 °C
    • Accumulated Precipitation Anomalies:
      • September: the historical average precipitation is 29 mm, with warming precipitation changes:
        • Moderate Warming: -3 mm 
        • High Warming: -5 mm
      • October: the historical average precipitation is 20 mm, with warming precipitation changes:
        • Moderate Warming: 4 mm
        • High Warming: 6 mm


Funding for the climate maps component of this project has been provided in part by the Canada Research Chair in Temporal Ecology and in part by the governments of Canada and British Columbia under the Canadian Agricultural Partnership, a federal-provincial-territorial initiative.
Funding is administered by the Investment Agriculture Foundation of BC. This project is part of the Farm Adaptation Innovator Program delivered by the Climate & Agriculture Initiative BC.