2013 Harvest & August Winegrowing Update


Fedrick Vineyard Pinot Noir Harvest

On Thursday, August 29th, we picked our first block of Pinot Noir of the season from Fedrick Vineyard (1.5 Tons of Clone 115). The fruit looked and tasted great with very little botrytis, most of which was dropped out in the vineyard. The fruit underwent a cold soak through the weekend and was inoculated with Assmanhausen yeast early in the week. We'll report on fermentation as it progresses.

August Winegrowing Update

Winegrowing conditions throughout the month of August experienced higher humidity under steady wind speeds. Mean temperatures exceeded while sunlight levels matched historical averages.

Regional average and low temperatures exceeded 10 year averages while also experiencing typical high temperatures. August 2013 recorded diurnal temperature variations that were lower than historical and recent averages. Solar radiation crept past historical averages while slightly trailing 2012 during August. Daily marine layers began to burn off earlier during the last half of August allowing more sunlight to reach the canopy.

Humidity levels continued to be higher than the historical average for the month of August. Also, only 2011 humidity levels exceeded levels that we experienced this August. Wind conditions increased in August and did not decrease as is typically experienced as the growing season progresses.

The following detailed comparisons attempt to place August 2013’s weather conditions in context with historical averages. You can download the complete report here.



Sonoma Coast / Petaluma Gap Wine Growing Temperature

The Petaluma Gap experienced mean daily and high temperatures that exceeded historical norms 3.12˚F during the month of August. Even though average high temperatures matched the previous 10 year average, diurnal temperature variations, were 3.04˚F lower than average, as low temperatures were above 10 year averages by 3.14˚F.

The same comparisons can be made with 2012 August temperatures. In 2013, August mean and minimum temperatures exceeded 2012 by 3.15˚F and 2.8˚F, respectively.

Solar Radiation

Sonoma Coast / Petaluma Gap Wine Growing Solar Radiation

Solar radiation levels of 544 Ly/Day were a mere 9.9 Ly/Day or 1.9% higher than average for the month of August. Similar to July conditions, August experienced a marine layer that lingered until almost midday, diminishing the total amount of sunlight reaching the vines.

August’s sunlight levels were mildly lower than those seen in 2012 by 14 Ly/Day or 2.2%.


Sonoma Coast / Petaluma Gap Wine Growing Wind Conditions

Atypical to late season diminishing wind speeds, wind conditions in August increased over July conditions and only slightly lagged the previous 10 year average for the month by 1.9%.

August 2013 wind conditions surpassed those of 2012 by 5.9%.


Sonoma Coast / Petaluma Gap Wine Growing Humidity

August humidity levels were once again higher than historical averages by 5.3% (78%). Even though marine layers shortened as the month progressed, humidity levels remained high than normal. however, evapotranspiration during August was inline with the previous 10 year average.

2012 was an average of 7.1% drier.


Although of supreme importance, weather, in and of itself, is only a single variable in a wine growing season. The resulting fruit quality when it arrives at the winery is determined by a myriad conditions such as timing of weather events, site micro-climates, geography/orientation, training/trellising, fruit set, canopy management, etc etc etc. 

This report is based on Petaluma Gap regional weather data obtained from the California Irrigation Management Information System (CIMIS) Petaluma East Station (144) and is meant to characterize general growing conditions for the region. It should not, in any way, be construed to represent the growing conditions for any one particular vineyard site.