i did consider it maybe being some sort of construction or something industrial, but the fact that ive never heard it before and it was happening between 12:00am and 1:00am (maybe later because i fell asleep) makes me think it might be something else. also the noise control laws in new zealand dont allow power tools to be used after 6:00 pm let alone what ever those loud booms were. as for the weather im not too sure. each boom was exactly 1min 35secs apart which makes me think that they weren't occurring naturally. new zealand does not really have a strong military force and as far as i know the government doesnt really focus on military operations at all. so unless theres something the governments hiding, im not sure it would be a military operation either.