The Department of Conservation says there is only one month a year they do not have to deal with whale strandings.
Nine whales had to be euthanised at Golden Bay near Farewell Spit on Thursday, after rough seas and strong winds meant refloating them was no longer an option.
Thirteen pilot whales from the pod became stranded on the beach on Tuesday morning. Five subsequently died and DoC staff and volunteers worked on Wednesday to try to refloat the rest.
DoC Golden Bay conservation services manager John Mason said staff had walked the whales into deeper water but they would not head out to sea and were found again on Thursday morning.
"We were hopeful they would make it back out but they started to exhibit a certain pattern of behaviour that didn't seem to want to change. They spent (Wednesday) afternoon basically trying to re-strand themselves on the beach."
Mr Mason said strandings there are extremely common because a large inter-tidal area confuses the whales as to which way is out. He said statistics over nearly 30 years show that August is the only month they have never had a stranding.
"It's always in the back of your mind over that Christmas-New Year summer period about have we had a stranding, are there any whales in the bay. You think about the different scenarios of where they might strand and how you might deal with it and who you've got around to help. But you really don't know."
Mr Mason said euthanasia is a more expensive option, but it was the best decision for Thursday's situation. He said local iwi said a prayer for the whales before they were put down.