Kate Middleton wears a green Sandro dress and espadrilles for garden picnic

Kate Middleton’s latest look proves that summer has officially arrived.

Today, the Duchess of Cambridge, 37, hosted a garden picnic in honor of the “Back to Nature Garden” she helped co-design.

Middleton wore a green short-sleeve dress by Parisian fashion brand Sandro, which featured a V-neck and pleated waist band. Although it normally retails for $370, the dress is currently on sale for $222 (aka 40 percent off).

Middleton accessorized the midi dress with a pair of summer-appropriate espadrilles. Her hair was business as usual (natch).

The Back to Nature garden originally debuted at the Chelsea Flower Show back in May. With the help of landscape architect Davies White, the duchess recreated the outdoor display, which is currently at the Royal Horticultural Society’s Hampton Court Palace Garden Festival.

The new exhibit is twice the size of the original and features a grassy hill for kids, a pond for activities, a bee-friendly meadow and several architectural details—like rustic dens, waterfalls and streams. (The purpose is to encourage children to spend more time outdoors.)

For the picnic, Middleton partnered with several charities, including Anna Freud Centre, Evelina Children’s Hospital, Action for Children and Place2Be. The event consisted of a treasure hunt and a bug-spotting activity before attendees sat down for a picnic in the garden.

BRB, purchasing this Sandro dress before the Middleton Effect kicks in.

Related: Kate shows off her project to Queen Elizabeth