The performance finally started half an hour late.

晚了半小时以后演出终于开始了。

《牛津词典》

I told the girl at the reception desk that I was terribly sorry, but I was half an hour late.

我对接待服务台的女孩说我很抱歉，迟到了半小时。

《柯林斯英汉双解大词典》

You're half an hour late, you know.

知道吗，你晚了半小时。

youdao

The walk began about half an hour late because it took longer than expected to depressurize the new airlock so the astronauts could step out into space.

CNN: Astronauts complete final spacewalk

Similarly, if invited for dinner at 9pm, showing up half an hour late is fine, unless the host specifically requests punctuality (in which case arrive around ten past).

ECONOMIST: Gulliver | The

In the end Mr Huhne was nearly half an hour late for his announcement because he had been speaking in the opposition day debate in the Commons on the Blue Tongue outbreak.

BBC: Sketch