South Island in March Caveats

Hello,
I will arrive in Wellington from California 10 March. Then from Picton I will rent a car 13-26 March dropping it at Christchurch airport from where I fly home. I will not be in the South Island low-season, nor will I there high-high-season when there's much competition for lodging, etc. I prefer to improvise my trips as I go and not plan too much. I don't think I will have to worry about school holidays during that period. But is s there anything l should be aware of?. Anything I should watch out for that could complicate my wanderings: holidays, conventions, events in certain areas, towns, that would fill up lodgings, whatever? I don't want to be a control freak and worry unnecessarily. But I would also rather not be blindsided by something I was unaware of. Advice appreciated.
Thanks in advance.

Nope, nothing much happening then that would make your holiday difficult.

Good time of year to be travelling the SI. You are in between the Ellerslie Flwer Show which will be huge in Chch, end of Feb & War Birds over Wanaka at Easter.
Do be aware that because of the rebuikd Chch has a huge shortage of beds at both the high end (most hotels were demolished) and the budget end (backpacker hostels ditto). Motels are full of people in Hi-vis & hard hats!