Melbourne is having its wettest start to a year in almost half a century, following one of the city's driest years on record.

Melbourne only received 374.4mm of rain during 2019, making it the city's driest year since 1997 and third driest in 164 years of records.

The remarkably low rainfall in Melbourne and many areas of Australia during 2019 was partially caused by a strong climate driver that peaked late in the year: a positive Indian Ocean Dipole (IOD).

However, once this positive IOD broke down and the Indian Ocean returned to a neutral phase, rain started returning to parts of southeastern Australia at the beginning of 2020.

In January, Melbourne collected 115mm of rain, making it the city's wettest month in just over two years. Then came February's 76mm, which was also more than any individual month in 2019. So far in March, Melbourne has picked up 65mm, already exceeding the long-term average for the month.

As of 9am on Thursday, Melbourne's running total for the year-to-date was 256.4mm. This is the city's highest total to this point in the year since 1973 and the sixth highest on record.

Melbourne's long-term average annual total is about 650mm. The city's wettest year was 967.5mm in 1916 and the driest was 332.3 in 1967.