Killyleagh, United Kingdom — Weather in September 2026

Climate Overview

Killyleagh, United Kingdom in September has mild conditions, with highs averaging 16.1°C (61°F) and noticeably cooler mornings. Rain falls on about 15 days this month, totalling around 94 mm. Sea temperature stays cool at 15.4°C (60°F).

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 17°C (63°F) at the start to 15°C (58°F) by month's end.

September sees fairly even rainfall, totalling about 93 mm across the month.

Expect around 7.7h of sunshine at the start of September, decreasing to 6.6h by the end.

Wind speeds pick up through the month, from 22 km/h (14 mph) to 28 km/h (17 mph).

The warmest days tend to fall around the 6th, averaging 17.8°C (64°F).

Compared to August, this month is about 2°C cooler with 0 fewer rainy days. Temperatures begin dropping heading into October.

Monthly September Averages

Temperature

16°C / 12°C

Feels Like

14°C / 9°C

Rain

15 days · 94 mm

Sunshine

7.3h / day

Humidity

81% — Very Humid

Wind

25 km/h

Wind Direction

SW (225°)

Gusts

42 km/h

Daylight

12.7 h

Cloud Cover

72%

Clear Sky Days

0.8

UV Index

3.3 — Moderate

Sea Temperature

15°C

Dew Point

11°C — Comfortable

Moon Phase

Waxing Crescent · 11%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

HighLow

Daily Precipitation

Rainfall

Daily Sunshine

Sunshine

Daily Wind Speed

Wind Speed

Sun Position

Sunrise 06:56

Daylight 12.8h

Sunset 19:42

What to Expect

Keep afternoons flexible as tropical showers are common — they typically clear within an hour.

Wet weather can spread across much of the day, so it is best to keep outdoor plans flexible.

1 of the last 5 yearly records were warmer than this month's long-run average.

Compare Months

Month	Temp	Feels Like	Rain	Sun	Humidity	UV	Status	Details
January	8°C / 4°C	4°C / 0°C	13days (73 mm) Wet	3.7h Poor	83% Humid	0.9 Low	Poor	View Details
February	8°C / 5°C	4°C / -1°C	14days (80 mm) Wet	5h Fair	80% Humid	1.5 Low	Poor	View Details
March	9°C / 5°C	5°C / 0°C	14days (73 mm) Wet	6.8h Fair	80% Humid	2.8 Moderate	Poor	View Details
April	11°C / 6°C	8°C / 2°C	11days (58 mm) Wet	8.9h Good	78% Humid	4 Moderate	Poor	View Details
May best	14°C / 9°C	12°C / 6°C	12days (58 mm) Wet	10.6h Excellent	78% Humid	5.4 High	Fair	View Details
June best	17°C / 12°C	15°C / 9°C	14days (75 mm) Wet	10.3h Excellent	78% Humid	5.6 High	Good	View Details
July best	18°C / 13°C	17°C / 11°C	14days (87 mm) Wet	9.4h Good	80% Humid	5.1 High	Good	View Details
August best	18°C / 13°C	17°C / 11°C	15days (94 mm) Wet	8.9h Good	81% Humid	4.8 Moderate	Fair	View Details
September best	16°C / 12°C	14°C / 9°C	15days (94 mm) Wet	7.3h Good	81% Humid	3.3 Moderate	Fair	View Details
October	13°C / 10°C	10°C / 6°C	15days (101 mm) Wet	5.2h Fair	81% Humid	1.9 Low	Poor	View Details
November	10°C / 7°C	7°C / 3°C	15days (93 mm) Wet	4h Fair	82% Humid	1.1 Low	Poor	View Details
December	9°C / 6°C	5°C / 1°C	15days (96 mm) Wet	2.8h Poor	84% Humid	0.6 Low	Poor	View Details

What to Wear

Bundle up with a warm coat, scarf, and closed-toe shoes. Thermal layers underneath give flexibility between indoors and outdoors.

A waterproof jacket or compact umbrella is recommended for occasional showers.

Packing List

Layered clothingLight jacketUmbrellaWaterproof jacketWaterproof shoes

Frequently Asked Questions

Expand all

Is September a good time to visit Killyleagh?

September is typically fair for visiting Killyleagh, with average highs of 16°C (61°F) and around 15 rainy days. Killyleagh, United Kingdom in September has mild conditions, with highs averaging 16.1°C (61°F) and noticeably cooler mo

Does it rain a lot in Killyleagh in September?

Killyleagh typically sees around 15 rainy days in September with 94 mm (3.7 in) of total rainfall. Pack a waterproof jacket.

Does it get cold at night in Killyleagh in September?

Nights in Killyleagh during September are cool at around 12°C (53°F). Bring a jacket or sweater for evenings.

What should I pack for Killyleagh in September?

With highs of 16°C (61°F) and lows of 12°C (53°F) in September, we recommend: Layered clothing, Light jacket, Umbrella, Waterproof jacket, Waterproof shoes. Comfortable walking shoes are essential.

Is September among the best months weather-wise in Killyleagh?

Yes, September offers some of the best weather conditions in Killyleagh with comfortable temperatures and lower chances of rain.

What is the UV index in Killyleagh in September?

The average UV index in Killyleagh during September is 3 (moderate). Sunscreen and sunglasses are recommended during midday hours.

How many hours of daylight are there in Killyleagh in September?

Killyleagh gets approximately 13 hours of daylight per day in September, with around 7 hours of sunshine.

Does it snow in Killyleagh in September?

Snow is uncommon in Killyleagh during September based on 10-year climate averages.

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