The climate has a major influence on both the quality and quantity of fruit, however, how climate effects the fruit is complex and not fully understood. Vine growth and development is influenced by rainfall, temperature, wind and sunshine. Viticulturally the weather conditions between October and March are critical and have a major influence upon quality and yield. Rain at harvest time, late January - March is significant in terms of the incidence of fungal diseases such as Oidium (powdery mildew), delayed ripening and berry splitting with the invasion of secondary infection.
The rainfall in the Swan Valley is 739mm and is winter dominant. During the growing season , October to March, the warm to hot temperatures lead to an early harvest and excellent levels of ripeness. Summer rains are very limited and are rarely a problem with the ripening of the fruit. The Swan Valley is fortunate to have a cooling sea breeze from the Indian Ocean most afternoons and evenings during summer. This cooling breeze can reach speeds of 25 - 30 knots of wind strength, and is a positive factor in the production of premium quality wines by lowering ambient temperatures.
The climate has a major influence on both the quality and quantity of fruit, however, how climate effects the fruit is complex and not fully understood. Vine growth and development is influenced by rainfall, temperature, wind and sunshine. Viticulturally the weather conditions between October and March are critical and have a major influence upon quality and yield. Rain at harvest time, late January - March is significant in terms of the incidence of fungal diseases such as Oidium (powdery mildew), delayed ripening and berry splitting with the invasion of secondary infection. 
