December 2010

RAINFALL

Below average rainfall in December did little to detract from the positive outcome of a much wetter winter-spring in 2010, and consequently, anabove average year overall. Although December rains across much of Geelong were average, the official BoM gauge at Geelong Airport found itself on theouter once again with a disappointing 30 mm, having missed out on a couple of nearby thunderstorms.

Otway catchments received average totals and better, and the northern and Bellarine suburbs again fared well. The catchments are now at 74% of capacity.

For the year, virtually all of the region received between 100% and 120% of normal annual falls owing to the continuing La Nina situation. Urban Geelong recorded around 650 mm, compared to the 30-year average of 520 mm. It was Geelong’s wettest year since 2001, when 714 mm fell at GeelongAirport and 657 mm across the suburbs.

TEMPERATURE & OTHER FEATURES

Geelong’s average daily maximum was 23.5 degrees C and minimums averaged 10.9ºC. The 19-year averages from the Airport are 22.7 C and 11.0 degrees Crespectively. The first 9 days of the month were much warmer than normal in maximum and minimum figures, but were somewhat counterbalanced by the cooler end of the month.

Maximum temperature was 30.7 C on the 3rd, and it was the only day over 30 degrees. The coldest day (19th) only recorded 16.5 C. Lowest overnight temperature was 4.7 C on the 22nd and warmest was 19.1 C on the 8th. Overall the year has been just fractionally (0.2 C) warmer than the Airport long-term normal.

Global warming continues to evade the Geelong region, with no unambiguous signal discernible. What has been discernible at Geelong Airport AWS since 1992 however, is the overall slight temperature increases that are clearly related to urban encroachment, automobile emissions due to a massive 70% road traffic increase and a bird manure-encrusted roof on the Stevenson Screen which houses the sensitive temperature instruments. (Photo available on request). There was one severe storm, on the 3rd, when strong winds and a heavy thunderstorm struck the city and northern suburbs depositing 20-30 mm of rain in less than an hour and creating chaotic flash flooding. There were four very windy days with the top gust reaching 72 kph on the 11th. For a complete summary of the year’s weather, please see the separate annual summary.

RAINFALL DATA