When you need to test durability.

Weather

View weather data

You can download PDFs of weather data (monthly and annual) for most years from 1970 to 2015 at right.

Tropical latitude

Townsville is at a latitude of 19° South. This is a truly tropical climate: the sun passes directly overhead twice each year. The region has a harsh, complex, tropical climate that is ideal for weathering tests and durability studies. The low latitude also means significantly less seasonal variation in radiation and temperature.

The region around Townsville is characterised as part of the ‘dry tropics’. This area has less rainfall (annual average about 1100mm) and higher radiation levels than ‘wet tropics’ regions north and south of Townsville.

While wet tropic areas have rainforests and sugar and banana crops, the dry tropics are areas of open rangelands and savannas that are often used for cattle grazing and production.

Chemical changes associated with weathering and degradation depend on temperature and Townsville’s temperature profile remains relatively high throughout the year and seasonal variations are minor.

Townsville faces the Coral Sea and the Pacific Ocean looking out towards Noumea (latitude 22°S) and Fiji (latitude 18°S). Allunga’s primary exposure site and laboratory facilities are approximately seven km from the coast.

Radiation

Allunga’s Townville site averages 7500 MJ/m² global solar radiation per year (the adjective ‘global’ meaning direct and diffuse) and this includes approximately 400 MJ/m² UV (below 385 nm). Its low latitude means there is a reduced atmospheric path length, which means higher radiation levels and less scattering so the Direct:Diffuse ratio is higher.

Rainfall and condensation

Rainfall can vary considerably from year to year, but exposure to moisture, most of which occurs through condensation is far more consistent. This is because humidity levels are often relatively high so that only small temperature changes are required for the dew point to be reached and for moisture to condense on exposed surfaces. We record the time that exposed surfaces are wet.

The cycling of moisture exposure and high radiation levels that often occur with Townsville’s night–day cycle is an important component of the natural weathering process.

Cyclone precautions

While the location is ideal for weathering tests and durability studies, this area, along with most of northern Australia, can experience cyclones over the summer from December to April.

Allunga has cyclone proof storage facilities and emergency plans to deal with these eventualities. Our cyclone plans have been put into action several times in recent years but only as a precaution — the Townsville region’s last serious encounter with a cyclone was in December 1971.