Further south, the Lake Taupo Cycle Challenge is already underway, although the MetService has tweeted it will be hampered by poor visibility.
"Take care if you are competing or driving in the Taupo area," the forecaster said.
The MetService said a heavy rain watch remained in place in Auckland, Northland, Great Barrier Island and the Coromandel Peninsula until tonight. There was a possibility this would bring short bursts of rain that reached "warning criteria", it said.
In Auckland, the heavy falls are set to last until 6pm and the city is forecast to have a high of 22C.
The dreary weather is expected to last into next week. MetService is forecasting rain every day in Auckland for the next 10 days.
Elsewhere, Hamilton and Tauranga are tipped to hit highs of 18C and 19C with heavy morning rain easing to showers in the afternoon, while Wellington is expecting 20C with occasional showers.
Rain is also forecast in New Plymouth and Napier, while Taumarunui - which had yesterday's top temperature of 24C - is forecast to reach 19C.
Rain is also set to fall across the South Island. Invercargill is the only place expecting sunshine and a high of 21C.
Christchurch can expect drizzling rain and a top of 17C, and Queenstown can expect 19C.
Otago residents still cleaning up from a deluge earlier this week aren't set to get any relief. MetService has issued a heavy rain watch for South Canterbury and North Otago beginning from 6pm.