The ACP is the result of fifteen years of study by Dr. John C. Freeman and Ms. Jill F. Hasling on possible astronomical effects on the long range prediction of the climate. The study was initiated to study hurricanes since 1985 and has been used operationally to predict the section of the US coast on which a named tropical cyclone is most likely to make landfall with an accuracy of 78%.
Recently a connection was made between the climate of countries in the temperate zones and the occurrence of El Niño or La Niña which are indicated by the ocean temperature near the equator. El Niño and La Niña are predictable and have been embraced by meteorologists and climatologists as the foundation of a serious science of long range weather prediction.
The second model used for the prediction is based on the orbit of the sun about the center of gravity of the solar system and the orbit of the moon about the earth. When these astronomical bodies are in moving in a certain way there are more or less El Niños and La Niñas.
The Two year forecast includes the following for selected cities.
- The average temperature for the month
- The total rainfall for the month
- The HDD for the month
- The accumulated total of HDD starting in July
- The CDD for the month
- The accumulated total of CDD starting in January
Each item is accumulated by the normal value.