You know the cost-of-living conversation. It's about Auckland rents and Wellington cafés and how expensive everything's become up north. But here's what nobody's talking about: South Island households are now spending $15,305 a year on groceries, and the climb has been relentless.

Four years ago, in 2020, that number was $12,509. Not cheap, but manageable for most families. Then came the steady march upward: $12,766 in 2021, $13,735 in 2022, $15,064 in 2023. This year it hit $15,305. That's $2,796 more than 2020. (Source: Stats NZ, food-price-index-regional)

Break that down and it's an extra $54 every single week. For four straight years.

Think about what $54 buys you at the supermarket. A full trolley of basics. A week's worth of school lunches. Three dinners for a family of four. Now imagine not having that money at all, because it's already been absorbed into your existing grocery bill just to buy the same stuff you bought in 2020.

This isn't an Auckland story. It's not even a city story. Christchurch, Dunedin, Timaru, Invercargill: every household south of Cook Strait is feeling this. And unlike rent, which you can escape by moving or downsizing, you can't opt out of eating.

The South Island has always prided itself on being more affordable than the north. Lower house prices, less traffic, a slower pace. But groceries don't care about your lifestyle choice. The weekly shop costs what it costs, and right now it costs 22% more than it did four years ago.

Here's the really uncomfortable bit: there's no sign this is slowing down. The jump from 2023 to 2024 was $241. That's smaller than previous years, sure, but it's still upward. Still another $5 a week gone. Still another notch tighter on the household budget.

Politicians talk about inflation like it's abstract. Central bankers manage it with interest rates and forward guidance. But for a family in Nelson or a couple in Queenstown, inflation is this: the same trolley of food that cost $240 a week in 2020 now costs $294. Every week. Without fail.

The data goes back 50 years. In 1975, South Island households were spending vastly less in real terms. The long-term trend has always been upward, but nothing like this. The last four years have compressed what used to take a decade into a single parliamentary term.

So yes, Auckland's expensive. Wellington's tough. But if you think the South Island has dodged the cost-of-living bullet, check your grocery receipt. That extra $54 a week tells a different story.