Frost Indicators and Maps


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Frost Indicators and Maps

Frost Indicators

The production of the frost and growing degree day maps of Marlborough was made possible through funding provided by both the Marlborough Grapegrowers' Association and New Zealand Winegrowers.

The maps were produced by NIWA, Wellington. The co-ordination of the Marlborough mapping project was handled by The Horticulture and Food Research Institute of New Zealand Limited ("HortResearch"), Marlborough. The maps have been produced as a resource for the grape growing industry, however, the information contained in the maps is applicable to the whole agricultural/horticultural sector in Marlborough.

The demand for maps indicating frost risk has arisen with the rapid spread of vineyards away from the central Wairau Plains. Long term frost records are only readily available for Blenheim. Many enquiries have been received regarding the frost risk of areas of land in other parts of Marlborough. The Blenheim records are not applicable to other areas.

The maps are to be used as a guide only. Accuracy of the data is indicated in the key on each map, eg: the frost free period graphs use 20-day intervals. The maps are intended as a point of first reference and people looking at making decisions regarding individual properties would be well advised to undertake detailed climate studies of properties on site.

Frost Maps

Marlborough has been divided into seven geographic regions, shown on the Frost Indicators map. Subject to your acceptance of the terms of the disclaimers set out below, you can select which of the seven areas you are interested in by clicking on the links displayed in the Frost Monitoring Locations table that correspond to the areas shown on the map.

  • GDD = growing degree days
  • FFP = frost free period
  • FF20 = 20th percentile first frost date (ie; early first frost date)
  • FF50 = 50th percentile first frost date (ie; median first frost date)
  • LF50 = 50th percentile last frost date (ie; median last frost date)
  • LF80 = 80th percentile last frost date (ie; late last frost date)

So, for each of the seven map areas there are 12 maps to choose from.

Viewing the Maps

Two copies of each map have been produced in Adobe PDF format.

The Small Map is 400 Kb-800 Kb and is designed for easy access over the web. This map contains no cadastral boundary information.

The Large Map is 1,000 Kb-6,000 Kb and contains the cadastral boundary information. These maps will take considerably longer to download.

To select an area of a map to view, select the Acrobat Viewer's zoom tool and click your mouse over the area you want to zoom in to. To zoom out, select the zoom tool, hold down the Control key on your keyboard and click.

Further Information

For further information you can contact Rob Agnew, (a scientist with HortResearch Marlborough, based at the Marlborough Wine Research Centre) by emailing him at


NIWA staff have prepared the maps exercising all reasonable skill and care. Nevertheless, NIWA can give no warranties that the maps are free from errors, omissions or other inaccuracies. Users of these maps will release NIWA from all liabilities, whether direct, indirect or consequential, arising out of the provision of this data.

Cadastral data - LINZ copyright. Cadastral boundaries are indicative only. Marlborough District Council provides no warranties in terms of property boundary positions.

The information contained in the maps or this summary page (as the case may be) is intended as a guide only and HortResearch does not give any prediction, warranty or assurance in relation to the accuracy of or fitness for any particular use or application of, any information or scientific or other result contained therein. Neither HortResearch nor any of its employees or contractors shall be liable for any cost (including legal costs), claim, liability, loss, damage, injury or the like, which may be suffered or incurred as a direct or indirect result of the reliance by any person on any information contained in the maps or this summary page. Accessing the maps shall constitute acceptance of the foregoing conditions.