Weather forecast builder for the GR 10

The GR 10 crosses the Pyrenees from Hendaye to Banyuls‑sur‑Mer, where conditions vary with coast, altitude, and season. April, May, and September tend to offer cooler air, steadier days, and fewer heat‑and‑thunder spells along much of the route. The Atlantic west is typically cloudier and wetter, the Mediterranean east drier and sunnier, while higher cols remain markedly colder year‑round, with summer warmth punctuated by showers and winter bringing frequent snow on the crest.

• Spring: Changeable with frequent showers and short clear windows; west stays wetter, east brighter. Higher passes hold lingering snow, with cold snaps dusting tops.
• Summer: Warm to hot with long days; mornings often clearer before cloud builds. Passing showers and brief thunderstorms frequent, wetter west, drier and sunnier east.
• Autumn: Variable with fronts and bright breaks; humidity fades and nights cool at elevation. West sees frequent rain, while east trends drier, with occasional downpours.
• Winter: Firmly wintry and unsettled; overcast and wet in the west, with widespread mountain snow. Clear, crisp interludes are short, and cold intensifies with altitude.