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Grapevine Cold Hardiness

Real-Time Monitoring

Critical temperatures for wine and juice grapes are determined using a method called “differential thermal analysis” as described by Mills et al. (2006).  These data are updated approximately weekly from approximately mid-October through mid-April. Data is collected from buds and canes (node positions 4-7) on mature vines grown at the WSU Irrigated Agriculture Research and Extension Center (5 miles north of Prosser, WA) and from nearby commercial vineyards.



Washington State University has developed a Cold Hardiness Model to predict grapevine cold hardiness anywhere temperature data is available. It is available both as an EXCEL sheet (to enter your own weather data), or via AgWeatherNet (for WA locations).

More information on modeled cold hardiness can be found at our Cold Hardiness Modeling page:

Variety Graphs

BUD10 is the temperature at which 10% of the primary buds will be killed; BUD50 and BUD90 refer to 50% and 90% bud damage, respectively. PHL10 is the temperature at which 10% of the phloem (bark) is damaged or when cane damage is starting. XYL10 is when phloem damage is complete and xylem (wood) damage is starting. This would be considered severe cane damage. Grapevines can survive more than 50% phloem damage and still be productive. When xylem becomes damaged, grapevine productivity and survival can be compromised.

Select a variety name below to see the current season observed cold hardiness.











Interpreting the Graphs and the Table


If the temperature lines in the graph (top two blue lines) cross over the critical temperature lines for buds, then damage has likely occurred. Please review the Resources in the right navigation bar for information on managing cold-damaged vineyards.


When we are at or approaching bud break, we will not be able to run exotherm analysis in grapes any more.  In previous years we have included the critical temperatures for several different varieties during the period leading up to bud break.  Since every variety responds differently to cold, this should be used only as a rough guideline.

  • Cabernet Sauvignon at first swell sustained no damage down to 25°F.
  • Merlot at full swell showed slight damage to the buds, phloem, and xylem at 25°F. More serious damage to the phloem and xylem occurred at 23°F. 
  • Chardonnay at budbreak showed slight damage to the buds and phloem at 27°F. More serious phloem and xylem damage occurred at 25°F. Buds were seriously affected at 24°F.


Preventing Cold Damage in Grapes:

Assessing Cold Damage in Grapes:

Responding to Cold Damage in Grapes:

Initial Cold Hardiness, Maximum Cold Hardiness, and Spring Frost Tolerance


The below table shows initial fall cold hardiness (mid-September) and potential maximum mid-winter cold hardiness for grapevine buds. It also shows frost tolerance of green tissue in the spring following budbreak.

Information is modified from Table 4 in Ferguson et al., 2014 (AJEV).


Initial Fall Cold Hardiness


Potential Maximum Mid-Winter Cold Hardiness


Frost Cold Tolerance- Post Budbreak


Barbera 13.8 -10.3 29.8
Cabernet franc 14.2 -13.7 29.8
Cabernet Sauvignon 13.5 -13.2 29.8
Chardonnay 10.8 -14.3 29.8
Chenin blanc 10.2 -11.4 29.8
Concord 9.0 -21.1 27.5
Dolcetto 13.8 -9.8 29.8
Gewurztraminer 11.1 -12.8 29.8
Grenache 14.0 -8.9 29.8
Lemberger 8.6 -14.1 29.8
Malbec 11.3 -13.2 29.8
Merlot 13.5 -13.0 29.8
Mourvedre 14.9 -7.8 29.8
Nebbiolo 12.0 -11.9 29.8
Pinot gris 10.4 -11.4 29.8
Riesling 9.3 -15.0 29.8
Sangiovese 12.7 -7.4 29.8
Sauvignon blanc 12.9 -12.8 29.8
Semillon 13.3 -8.3 29.8
Sunbelt 10.8 -20.4 27.5
Syrah 13.5 -11.6 29.8
Viognier 11.8 -11.2 29.8
Zinfandel 13.3 -11.9 29.8