Practical
Weather on the Seacoast
Portsmouth's weather is coastal, which means milder winters, cooler summers and more wind than the rest of New Hampshire. Plan for the wind and you will rarely be caught out.
By season
What each season actually feels like
Written from the pattern rather than from averages. Individual weeks will contradict all of this.
March to May
Spring
Slow and reluctant. The ocean holds the cold well into May, so Portsmouth runs several degrees behind inland New Hampshire.
- Pack
- Layers, a waterproof shell, and shoes you do not mind soaking.
- Plan
- Museums and interiors still carry the day. Many seasonal operators have not opened yet.
June to August
Summer
Warm rather than hot, with sea breeze taking the edge off afternoons. Fog can sit on the harbour while it is clear a mile inland.
- Pack
- A jumper for the evening — the temperature drops fast once the sun goes.
- Plan
- Everything is open and everything is busy. Book dinner; arrive at beaches early.
September to November
Autumn
The best weather of the year. Clear, dry, low humidity, and the light turns spectacular through October.
- Pack
- A proper jacket by late October. Wind off the water is the deciding factor.
- Plan
- Peak walking season. Foliage weekends compress accommodation hard.
December to February
Winter
Cold, often grey, sometimes brilliantly clear. Coastal storms bring wind and mixed precipitation rather than reliable deep snow.
- Pack
- Windproof outer layer, warm hat, boots with grip for brick pavements.
- Plan
- A genuinely good time for restaurants and theatre; a bad time for boats and house museums.
Next
Weather-proof the trip
- Season by season
What is actually on, month by month.
- What can I do today?
Filter by indoor, outdoor and free.
- Tides
The other variable on the water.
Something out of date on the weather reference? Send a correction with a source and we will update the record and its verification date.