2012 Petaluma Gap Weather Analysis

The weather throughout the Petaluma Gap region during the 2012 growing season (Apr-Oct) was slightly warmer, sunnier and drier, compared to the previous 10 year average (2002-2011). 

By now we have all read the numerous 2012 harvest reports of “abundant yields of superior quality”. As we will see here, the favorable (near perfect) weather conditions support these claims (at least in the Petaluma Gap).

Temperature, Solar Radiation, Humidity and Wind are the main climatic influences of specific interest to winegrowers during our growing season here in Northern California. (Precipitation, primarily rainfall, rarely occurs during the growing season.) These metrics are used to gauge vine water needs, ripening potential and fungal/disease pressure, among others.

The mean daily temperature was 58.1˚F, 0.4˚F above average. The average maximum temperature was 74.1˚F, 0.7˚F above average and the average minimum temperature was 45.9˚F, 0.5˚F above average. This all equates to a warmer growing season than average.

Sunlight (Solar Radiation) is another important metric in this region. The amount of sunlight to reach the leaves and clusters during the growing season regulates sugar production and flavor ripening potential. Higher solar radiation equates to less fog and/or cloud cover. The average solar radiation was 540.7 Ly/Day, 5.5% higher than average.

The 2012 growing season experienced lower than average humidity levels of 72.7, 1.1% lower than the previous 10 year average. Generally speaking, lower humidity, combined with higher temperatures and increased sunlight equals less vineyard treatments.

Adequate air flow through the fruiting zone is essential to alleviate fungal/disease pressure. Due to the lower humidity levels, combined with the warmer sunnier conditions, the below average wind conditions in the region proved not to be a major concern. The average wind speed in the region was 3.7 mph, 10.1% below average.

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