It's the height of summer "down under," time for tennis play at the AustralianOpen in Melbourne, a city known for its wide swings in temperature and weather.The average temperature extremes during the Open include a high of 78F, or25.6C and a low of 57F, or 13.9C. But averages do not begin to tell the wholestory.

On one hand, daytime temperatures can top 110F, or 43C, easily hot enough toaffect play dramaticly. This happens when desert heat from the heart ofAustralia sweeps southward ahead of cold fronts. Gusty winds and dust canaccompany these hot blasts, which normally have very low humidity.

At the same time, Melbourne's proximity to the South Ocean, always a cold bodyof water, means that cool winds are common. When such southerly winds coincidewith rain, it can feel downright chilly with daytime readings not far from 59F,or 15C.

While not a wet climate during summer, Melbourne does get measurable rain onabout one day in three during mid-January. Occasionally, there is thunder andlightning.

While the primary facility boasts a retractable roof and thus allows forall-weather play, many matches are held on open-air courts subject tocancelation due to rain or heat. For example, play during Jan. 28-30, 2009, wasaffected by the heat as temperatures soared above 110F, or 43C.

Weather on Tuesday should not hinder play in any significanr way. The high willbe near 73F, or 22.5C, with sunny intervals and a light southwesterly wind.

This year, scheduled play, in light on Monday's opening, will run 14 days, orthrough Jan. 31.

By Senior Meteorologist Jim Andrews