Seasons, and why yours might not match

What changes in the park, and when

The park keeps the season of the city you are looking at, not the season where you are sitting. Look up Sydney in July and you get winter: bare branches, dull grass and no flowers, while it is high summer in Oslo on the same afternoon. This page explains how the season is chosen and what each one changes.

How the season is decided

Three things go into it: the city's local date, its latitude, and the meteorological convention of three whole months to a season.

• The date is the city's own. It is worked out from the time of the observation plus the city's offset from UTC, so a city that has already rolled into the first of December gets winter while yours is still in November.
• The hemisphere flips it. South of the equator, March is autumn and September is spring.
• Near the equator there is no swing to show. Within about ten degrees either side, the vegetation stays green all year, so Quito in December is not put into bare winter trees the way Denver is.

What each season changes

Spring

The trees are in blossom, and a tree in blossom is not a green tree with flowers stuck on it: the whole crown is the blossom, white on one tree and pink on the next, with the variety across the stand rather than within a single tree. Petals drift down and settle. The grass is at its brightest, and the beds are pinks and whites with a lime and a sky blue among them.

Summer

Deep green everywhere, full canopies, and the brightest beds: coral, gold, orange, lilac, mint. This is the palette the park was built around; the other three seasons are departures from it.

Autumn

The canopies turn, one colour to a tree rather than a mix within each crown — a turning tree is the same leaf all over, and five shades in one canopy read as a fruit salad. Leaves come down and gather on the grass, which itself goes olive. The beds are ambers and burnt orange.

Winter

No canopies at all: the crowns are replaced by bare limbs, which is the only season where the trees are modelled differently rather than just recoloured. The grass goes grey-green, the bushes go to brown, and there are no flowers — beds of bare earth ringed in iron, which is what a park bed looks like in February.

Season and weather are separate

The season sets the planting; the weather sets the sky. They can disagree, and they should — snow in a city that is in spring is perfectly ordinary, and so is a warm bright day in the middle of a northern winter. The globe will show you blossom under falling snow if that is what the city is actually having.

The flowers

Two kinds, planted the way a park plants them. Formal beds ring the fountain on the first band of grass outside its paving, where everyone walking round the water passes them: cut plots of turned earth, edged in low iron hoops, each planted with a heart of one colour and a ring of another, because bedding is planted in blocks rather than mixed. Further out the park is informal, and the flowers there come up in clumps of one, two or three — a clump being one plant that has spread, so it is one colour.

Every flower is a twelve-petal daisy with three leaves, extruded rather than flat: a flat petal disappears when you see it edge on, which at standing height in augmented reality is most of them.