Clare’s climate is Mediterranean with typically warm to hot summers and cool to cold winters.
While summer in the Clare Valley is technically warm, maritime breezes have a moderating effect, and there are often drastic temperature drops from day to night. This wide diurnal variation in daily temperature leads to slower and more even ripening, allowing us to make some of the best Rieslings in Australia and plush medium-bodied reds.
In the height of summer when the grapes are ripening, the daily maximum temperature is nearly 30°C and the average night-time minimum is only 13°C. In winter, the mean maximum temperature is 14°C and the average minimum is 3°C.
The region has an annual rainfall of approximately 600 mm or 24 inches which occurs mostly in winter or spring. Summer thunderstorms provide welcome relief from the dry summers, providing vital soil moisture and filling the rain water tanks.
Spring frost can be an issue on low-lying vineyards, particularly on the eastern and southern fringes of the grape growing region and on some of the river flats to the northern end of the valley. Damage from hail is fortunately only very occasional and is generally considered a low risk. Although a rarity, there have been recorded snowfalls in the Clare region.
Prevailing wind directions are consistently south-west to north-west in the mornings but are highly variable, from the north, south, east or west, in the afternoons.
“More than any other district, the Clare Valley throws into question the accuracy of the heat summation index as a measure of climate,” James Halliday says. “The style of the wines is inconsistent with a climate seemingly so warm – the continental climate and cold nights in the growing season provide the answer,” he explains.
Aspect, slope & sunlight
Aspect, slope & sunlight
Sunlight is an essential ingredient in the growth of both the vine and the grape and so the location of a vineyard relative to the sun (called “aspect”) is important.
In the Clare Valley, the warmest aspects are those facing north, north east and north west.
The westerly aspects are cool in the morning but are exposed to hot afternoon sun, whilst the southern aspects are the coolest.
Vines higher up a slope will receive more sunlight than those lower down a slope.
The Clare Valley lies nestled at the northern end of the Mount Lofty Ranges in the Mid-North region of South Australia. Ranges of hills, running north-south, form a series of ridges, foothills and valleys, home to the region’s vineyards. Elevated vantage points such as Paulett’s Wines cellar door or the Quarry Hill Lookout offer some of the best views of the vineyards which form a patchwork across the rolling foothills. Hidden away on the western side of the Clare Valley is a locality called Skillogallee where you can get off the beaten track and explore a handful of wineries perched on hidden hillsides and tucked away in quiet valleys.
A water shed separates the northern half of the Clare Valley from the southern half with the northern catchment running into the Broughton River and the southern catchment feeding the Wakefield River. Surface water resources are highly dependent on rainfall and the major rivers are ephemeral watercourses, punctuated by many permanent pools primarily sustained by ground water. Locals will tell stories of adventures swimming in the ‘Island Pool or under the bridge at Undalia.
The region has a higher altitude than most wine regions in South Australia with many vineyards situated at 400-500m above sea level. Varying altitudes to 608m (Mt Horrocks) cause wide diurnal temperature variation from summer’s day to night, ensuring cool nights, even in the heat of summer, allowing the fruit to ripen evenly and slowly. It is the secret as to why grapevines prosper in the Clare Valley Riesling and our greatest asset in adapting to climate change.
While there are no legally-defined subregions in the Clare Valley, the topography naturally divides the region into smaller localities. Many wine lovers would be familiar with localities such as Auburn, Watervale, Sevenhill, Polish Hill River and Clare.