An up-to-data knowledge of weather conditions was urgently sought in the Pacific. To deny the enemy this advantage, stringent security measures were adopted, and weather information was transmitted in secret codes and cyphers. Sometimes, Japanese-coded reports were intercepted, and broken to glean weather information. Translations of captured Japanese documents—weather summary maps—by the US Pacific Fleet, indicated highly organised and efficient meteorological procedures by the enemy. The Japanese had been planning and preparing for war for a long time, and had obviously included the weather as a salient factor in their calculations. They probably made more use of the weather than any other nation. This is evidenced by their good timing of the landings at Milne Bay and at Buna and Gona in 1942, and generally in their southward advance in the south-west Pacific. They usually advanced under a protective cover of cloud and rain.

When General Macarthur's South-West Pacific headquarters was established in Brisbane in July 1942 it contained a meteorological section staffed by members of the RAAF Meteorological Service. This section provided daily briefings of expected weather conditions over the South-West Pacific area. In July 1943 this section began producing the Tropical Weather Research Bulletin which contained scientific papers dealing with the mechanisms producing weather conditions affecting military operations in the area. The leaders of this section were Squadron-Leader W. J. Gibbs of Sydney and Squadron-Leader R. A. E. Holmes of Perth.[7]

Bureau of Meteorology