Saint Peter Port (Sark) weather in September

September in Saint Peter Port: nice, a little rain, with clean air — an excellent time to visit.

Updated September 2026 · climate normals from ERA5 reanalysis

Saint Peter Port Guernsey · British Isles · City85
  1. 53Jan
  2. 62Feb
  3. 68Mar
  4. 78Apr
  5. 83May
  6. 88Jun
  7. 92Jul
  8. 89Aug
  9. 85Sep
  10. 71Oct
  11. 60Nov
  12. 54Dec

#4 of 12 months in Saint Peter Port · #505 of 1413 destinations to visit in September · comfort 85/100 (tier A)

Days
19°C
Nights
14°C
Wet days
9
Sun
9.5 h
Humidity
81%
Daylight
13 h
Saint Peter Port, Guernsey
Photo: Man vyi · Public domain

Traveller notes on Saint Peter Port in September

Other months in Saint Peter Port

There isn't much January-specific forum detail for Saint Peter Port itself, but Guernsey's general weather threads agree conditions are genuinely variable this time of year and can turn on short notice. The island's own climate record fills in the rest: this is a proper Channel Islands winter, with frequent rain, mild but chilly daytime temperatures, and wind that regularly gusts strong enough to keep umbrellas at home in favor of a proper waterproof coat. Daylight is short too, so plan outdoor harbor walks for the middle of the day.
ChannelIslandsWinterResident · January · 1 month ago · Read more on Tripadvisor ↗
Forum posters name July/August as genuine high season - busier streets and traffic in St Peter Port, but with the reliability upside that ferry cancellations due to bad weather are far less common in summer than other times of year. The town itself is described as hilly enough that finding flat accommodation is a challenge, though it's consistently called a lovely base for 2-4 days, with a strong restaurant and pub scene. Clifftop walks are named a highlight of a July visit, and posters recommend day trips by ferry to the quieter neighboring islands of Herm (walkable in under three hours) and Sark for a slower-paced contrast to the town. The standard caveat: weather can still be fickle even in summer, so posters suggest padding an extra day into the itinerary to guarantee at least one clear day for outdoor plans.
Tripadvisor community · July · 1 month ago · Read more on Tripadvisor ↗

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Saint Peter Port climate normals — September

Daytime high19°C / 67°F😎 nice
Nighttime low14°C / 58°F
Feels like (high)18°C / 64°F
Sea temperature18°C / 65°F🧊 bracing
Rainfall61 mm / 2.4 in🌦 some rain
Rainy days9 days
Humidity81%💦 very humid
Dew point13°C / 56°F
Sunshine9.5 h/day
Daylight12.6 h
Wind34 km/h / 21 mph
Air quality (US AQI)44🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Saint Peter Port in September

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Shoulder seasonschool holidays in 3 of the markets that fill it, an ordinary month(estimated)

JFMAMJJASOND

Peak crowdsBusyShoulder seasonQuiet

Best months for Saint Peter Port's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherSaint Peter Port's weather peaks June–August, best around July.

JFMAMJJASOND

Best weatherFair weatherToughest weather

What's on in Saint Peter Port in September

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Season

    Herm and Sark boat season

    15 Apr – 15 Oct · usuallySummer season opens

    The small boats to Herm, Sark and Alderney run frequently from the harbour through the season and thin out sharply after October. Half the reason to be based here is the day you spend on another island. Source ↗

What's on around the world in September →

Nearby, and something's on

Within 300 km of Saint Peter Port — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Saint Peter Port?

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Saint Peter Port in September — FAQ

Is September a good time to visit Saint Peter Port?
September in Saint Peter Port: nice, a little rain, with clean air — an excellent time to visit. It ranks #4 of 12 months for Saint Peter Port on SeasonMap's comfort score (85/100).
What is the weather like in Saint Peter Port in September?
In September, Saint Peter Port averages a daily high of 19.2°C and a low of 14.2°C, with about 61.1 mm of rain over roughly 9.3 rainy days.
What is the air quality in Saint Peter Port in September?
Saint Peter Port has a mean US Air Quality Index of about 44 in September.

Within 300 km: Bournemouth's New Forest heather around 1 Aug – 10 Sep, and Bath's Jane Austen Festival on 11–20 Sep.