"We've got more hot temperatures in the east: Napier, Hastings, Gisborne, are looking at 35C and 36C tomorrow and 26C for Auckland."
Elsewhere, a slow-moving front trucking over the southern end of the South Island would likely bring rain and cloud to those in western areas.
A heavy rain warning is in place for much of the lower West Coast, with between 300mm to 500mm expected in areas.
But the weather would be mainly fine in the east with high cloud and northwesterlies developing later in the day.
"There are likely to be a couple of hot spots, 34s and 35s for Ashburton, Blenheim, Christchurch," Pyselman said.
Temperatures throughout New Zealand will remain warm through Monday before another front cools things down on Tuesday and Wednesday.
And while temperatures will be cooler, they will really be closer to the average for this time of year.
"Things are definitely above average at the moment," Pyselman said.
"There's a warm feed coming from up over Aussie, the northwesterly flow drags warm air down here over us.
"As those westerlies blow over the main ranges, it dries out and compresses as it comes back down. That's why the eastern areas get so hot."
Unfortunately, Pyselman did not anticipate the mercury would skyrocket for Waitangi Day on Thursday.
"It's never a given but it looks like this is how things are going to play out once this warm air flushes out and we return to a southwest flow," he said.
"Wellington is a pretty fine looking day with northerly breezes. Christchurch has a fine start to the day and then it's clouding up with drizzle later in the day.
"In Auckland, temperatures will be more what we would say normal and partly cloudy - about 23C-ish.
