White Hoarfrost, Saint Martin's Summer

White Hoarfrost, Saint Martin's Summer of 1874, now in the Museum Barberini, captures a meteorological curiosity: a late warm spell in autumn — known as Saint Martin's Summer in French tradition — that produces hoarfrost at night while allowing mild temperatures by day. Sisley was drawn to these threshold conditions precisely because they offered visual paradoxes: frost on ground that looks simultaneously wintry and autumnal, the last green-brown vegetation beneath a white rime. The subject demands careful management of colour temperature to suggest both warmth and cold simultaneously — a challenge well suited to his chromatic sensitivity.

The peculiar quality of hoarfrost — crystalline but also softening edges — is suggested by slightly diffused contours on vegetation and ground rather than the crisp definition of hard frost or ice. The palette blends warm ochre and rust tones of remaining autumn leaves with the cool whites and blues of frost, creating an ambiguous seasonal atmosphere.