A haze hanging over Tauranga this morning was likely the result of a combination of the humidity, heat, a still night and sea spray.
Metservice meteorologist April Clark said the humidity in Tauranga this morning was quite high.
She said the humidity combined with the high that had been hanging over New Zealand this week had created "inversion", where particles in the air - such as those created by salty sea spray - could become trapped closer to the ground than usual.
Over time and in windless conditions that could build up and become a haze.
She said today's haze was already mostly dissipated by sea breezes by mid-morning but it could return tomorrow morning if the high sticks around.
The overnight low last night was 16 degrees and yesterday was the hottest day of summer so far, matching Tuesday's high of 24 degrees.