There are weather stations around the Canterbury area. Below are some useful links.

Diamond Harbour  Click Here
Chateris Bay  Click Here

Lyttelton

for the Lyttelton Port Company current conditions and forecast Click here
alternatively for 'Weather Underground' Click Here

Port Levy  Click Here

Also a great website/app PredictWind, free version gives forecast to 8km radius, updated hourly.

Gives very delailed information that can be more precise than Metservice. Create a log-in and use the app on your Cell Phone  Click here

Three more sites -

Metservice  https://www.metservice.com/national/home

Metservice marine  Click here

Windy.com  https://www.windy.com/?-42.220,165.372,7