RECENT rain has come as a welcome relief for Yamba after the coastal town recorded its driest February in 140 years.

According to Bureau of Meteorology data, a meagre 3.6mm fell in total during February. It was the least amount of rain that has been recorded since observations began at the Yamba Pilot Station in 1877, beating the previous record of 5.8mm set in 1926.

The average maximum temperature last month in Yamba was also an extreme, and at 28.3°C it was the highest average recorded since 1903.

Not to be outdone, Grafton broke records of its own, notching up its highest recorded maximum temperature, with the mercury hitting 45.8°C on Sunday February 12 at the Grafton Agriculture Research station, edging past the previous record of 44.6° set in January 2004.

Grafton Research Station also clocked the record highest February mean temperature of 26.9°C, one degree warmer than last year.

Bureau of Meteorology climatologist Agata Imielska said there were a number of conditions that produced the warm and dry conditions.

"For the whole Northern Rivers region, rainfall has been below average since September or October, and these drier conditions have exacerbated the heat as well," she said.

"Generally that fact is it's been dry and warm. Also, we haven't been seeing either cool conditions coming in and breaking up the heat or heavier rainfall events that break the heat up and give some relief from the hot conditions.

"We've been seeing persistent northerly flow which has brought warm air from central Australia which was causing the warmer conditions, and also for quite a few months north-westerly winds on the other side of ranges, so rainfall was sticking to the west of the Great Dividing Range."

Summer in the Clarence Valley was punctuated by frequent heatwaves, and Ms Imielska said as a result there was little relief from the heat.

"The breaks that we got weren't really that cool, but rather they were closer to what would be average for that month, so it was season characterised by back-to-back heatwaves and a general lack of cool conditions," she said.