Sulmona Geography & Climate

Sulmona sits in the middle of the Valle Peligna, and almost everything about the town follows from the shape of that basin.

A closed basin

The valley is a broad, flat floor at around 400 metres, roughly fifteen kilometres across, walled in on every side. It was a lake in the Pleistocene, and the flatness of its bottom is lake sediment. Because it is enclosed, air sits in it: cold pools here in winter and heat pools here in summer, and both last longer than they would in an open valley.

Monte Morrone

Immediately east the ground goes up in one movement to the ridge of Monte Morrone, which reaches 2,061 metres. From the square the wall of it is the view. It is a fault scarp, and the fault is still active.

The Maiella

Behind Morrone rises the Maiella massif, the second-highest group in the Apennines, with Monte Amaro at 2,793 metres. It is a national park, bare limestone above the treeline, riddled with caves and hermitages.

The western wall

On the other side stand the Monti Marsicani and Monte Genzana, and beyond them the Abruzzo national park. The mountains on that side are wilder and wetter, with bear and wolf in them.

Two gorges

Water leaves the basin north through the gorge at Popoli, where the Aterno and the Sagittario join to become the Pescara; the Gole del Sagittario, to the southwest, is a limestone canyon and a nature reserve.

Fault country

The whole basin is bounded by active faults, which is why it has been flattened repeatedly and why it is also full of springs.

Sulmona has a continental mountain climate made more extreme by the basin it sits in.

Winter

Winter is genuinely cold. Daytime highs hover near 8°C and nights fall below freezing regularly from December to February. Snow falls on the town most winters, sometimes heavily, and lies for days; the mountains around it hold snow for months.

Cold air pooling

Because the valley is closed, cold dense air sinks into it and stays. Sulmona records lower minima than places higher up the mountainside, and morning fog on the valley floor in winter is common while the ridges above are in sun.

Spring

Spring is the most variable season and the most attractive. April and May are green and mild, with the snow line retreating up Morrone in plain view from the square, but a cold snap in April is normal.

Summer

Summer is hot and dry, with highs regularly above 30°C in July and August, but the altitude and the dryness make it far more bearable than the Adriatic coast, and nights cool off sharply. Thunderstorms build over the Maiella on summer afternoons and can be violent.

Autumn

September and October are warm, settled and clear, with the best light of the year on the mountains. Rain increases through November.

Rainfall

Precipitation is moderate overall, concentrated in autumn and spring, with a dry midsummer. The mountains either side take far more than the valley floor does.

What to bring

Layers in every season, and proper footwear if you intend to go up Morrone at any time of year.