A "mackerel" sky is so called because this particular mottled pattern resembles the scales of a mackerel.
A mackerel tabby cat's pattern is so named for the same reason! The Tabby has the very same pattern as the one in the skies over Dunedin tonight.
And here was the vantage point. A millionaire's view enjoyed by the Tabby's blog team members. We were sitting on the deck of Swell, the new cafe on the St Clair Esplanade. A brilliant spot.