During the takeoff of Flight 325, there was a severe thunderstorm with very heavy rain to the south of Sydney Airport and another storm to the north. The weather conditions were not favorable for a safe takeoff. This information is consistent across multiple sources, including the Wikipedia page for Ansett-ANA Flight 325, which states, "Around the time of takeoff there was a severe thunderstorm with very heavy rain to the south of the airport and another to the north." For more detailed weather observations, one can refer to the Bureau of Meteorology's website that provides access to Mascot weather forecasts, warnings, observations, and radar and satellite imagery.