Shelf prices for fresh food change far more across a year than prices for packaged goods. The reason is that fresh supply cannot be manufactured on demand.
Growing seasons set produce supply
Fruit and vegetables become abundant when the nearest growing region is in season, and abundance pushes prices down without any promotional decision being made.
Out of season, the same item is sourced from a distant region or a controlled environment, both of which cost more to produce and to move.
The price a shopper sees is therefore mostly a statement about where the item came from that week.
Freight distance is a large part of the tag
Fresh goods travel refrigerated, on tight schedules, with losses along the way. Each of those factors adds cost that scales with distance and time.
Fuel prices flow through quickly for this reason, and a sustained rise in transport costs reaches fresh departments before it reaches shelf-stable ones.
Local sourcing is cheaper when it is available, which is exactly why the seasonal price floor coincides with the local harvest.
Meat follows a longer cycle
Livestock supply responds to decisions made months or years earlier, since animals take time to raise. Producers cannot expand quickly when prices rise.
Feed costs are the dominant input, so grain markets move meat prices with a lag. A poor grain year shows up at the counter well after the harvest.
Processing capacity adds a second constraint, because a bottleneck between farm and store can raise retail prices even while producer prices fall.
Weather compresses everything
A frost, a drought or a storm in a major growing region removes supply that cannot be replaced within the season, and prices respond sharply.
Because the affected volume was already committed to buyers, the shortage moves through the supply chain quickly rather than being absorbed.
Recovery depends on the next planting or the next cycle, which is why these spikes last months rather than weeks.
How the pattern shows up in store
Items at their seasonal low are usually the ones promoted heavily, since the retailer can offer an attractive price without giving up margin.
Substituting between similar items in the same category, rather than waiting for one item to fall, tracks the seasonal pattern more effectively.
Frozen and canned versions are processed at harvest, so their prices behave more like packaged goods and can undercut fresh badly out of season.