The National Climate Centre is checking its sunshine figures for 2008.
Initial results showed Whakatane had 2703 hours of sunshine last year - almost 200 hours more than Blenheim.
But staff at NIWA were surprised at the high level of sunshine recorded in the Bay of Plenty town and are conducting extra tests to check that the figures are correct.
NIWA says Whakatane usually averages about 2400 hours of sun.
A second monitor has been installed there to record sunshine levels and compare them with the original results. The testing will take a month.
Mayor Colin Holmes says he is quietly confident Whakatane will hold on to the title of sunniest town.
Mr Holmes says a sweltering start to 2008, including a drought, was probably the secret behind the added sunshine in the area.
He says he will hold off any gentle ribbing with Blenheim until results are confirmed.