International modelling and warm sea temperatures suggest an El Nino system will develop this year, according to the Bureau of Meteorology.

Six out of eight models surveyed by the bureau indicate El Nino thresholds may be reached by July, but the bureau cautions the models have lower accuracy when forecasting during the autumn months.

It says warming sea surface temperatures in the eastern Pacific Ocean and the downward trend of the Southern Oscillation Index are typical indicators El Nino is on its way. However, trade winds and cloudiness have shown no significant shift away from neutral.

El Nino is often associated with below average winter-spring rainfall over eastern Australia and warmer than average winter-spring temperatures in the south.

The bureau forecasts the neutral Indian Ocean Dipole is likely to remain at least until the end of winter.