Aucklanders heading to the beach today have a greater selection than yesterday after some of the city's most popular spots had their warnings lifted - but one local favourite has been issued with a rare black mark after a recent sewage spill.
According to Auckland Council's Safeswim website, much of the North Shore is now considered safe, as is the majority of the Hibiscus Coast.
But Point Chevalier beach today presents a "very high risk of illness from swimming" after a recent wastewater overflow.
Several other Auckland beaches are still considered "high risk" today, including St Heliers and Kawakawa Bay, but the vast majority are rated as safe.
The situation is a huge improvement on yesterday, which saw widespread warnings after bursts of torrential rain and storms battered Auckland over the weekend, putting stress on parts of the storm and wastewater networks.
The red alert classification is triggered by a direct measure of faecal indicator bacteria, Enterococci, in the water.
It denotes a greater than 2 per cent chance of getting sick from swimming at a beach.
A black alert, which Point Chevalier beach is currently under, indicates a "very high risk" of illness from swimming and means the water was directly contaminated by human faeces, and not just the Enterococci bacteria that could be from the gut of any animal.
National's Environment spokesperson Scott Simpson has called for a formal investigation into the state of Auckland's beaches.
"It's an appalling state of affairs that has only got worse in the past three years. In many cases this pollution flows directly into the already compromised Hauraki Gulf," Simpson said.
"The fact that as many as one in ten people swimming at popular Auckland beaches are likely to become ill highlights the just how polluted those beaches are.
"The sad thing is, people are missing out on their chance to swim during the peak summer holiday season yet again."
According to the Safeswim website, their water quality forecasts take account of rainfall, wind, tide, sunlight and beach type.
They are made using high-frequency targeted sampling on top of historical monitoring results, and are underpinned by the best available meteorological data, including readings from rain radar and an extensive network of rain gauges.
Safeswim's forecasts are automatically overridden if sensors detect unpredicted events – like a wastewater overflow in dry weather – that are likely to cause a public health risk.
Safeswim is overseen by an independent panel of public health and water quality experts and is required to meet performance standards adopted from the United States Geological Survey (USGS).
Beaches in the Auckland region proved a popular spot on Tuesday, with temperatures hitting 27C.
Another boomer day is forecast for Wednesday, with a 25C high during the day, and an overnight 'low' of 17C.
Paeroa had the national high on Tuesday, at 29.9C, while Hamilton hit 27C.
Fine weather is forecast for the majority of the North Island and the Marlborough and Nelson regions Wednesday.
Showers could hit most other areas of the South Island on Wednesday. But in good news for cricket fans, a rain free day is forecast for Christchurch for the ongoing second test between the Black Caps and Pakistan.