The royals engagements of a wreath-laying ceremony, a public walk through Seymour Square and a flying day at Omaka Aviation Heritage Centre with Sir Peter Jackson will hopefully not be affected by the weather.
As the Duke and Duchess travel north to Auckland on Friday, patches of rain will pass across the north of the country.
However, the Duchess can leave her wool coats in Wellington, as the temperature is expected to stay in the mid-20s in Auckland and Waikato.
Mr Corbett said patches of rain would pass across Auckland on Friday which could affect the match-sailing race at the Viaduct.
Waikato can also expect some showers on Saturday and people eager to catch a glimpse of the royal couple when they do their walkabout in Cambridge might get a bit damp.
"Assistants [to the royals] will have to have umbrellas at the ready,'' Mr Corbett said.
When the royals travel south to Dunedin on Sunday they can expect some fine weather at last.
"Certainly Sunday and Monday are looking a lot better,'' Mr Corbett said.
The Duchess of Cambridge and Prince George arriving at Government House in Wellington. Photo / NZH
Follow Life & Style on Twitter and Facebook.