Belfast weather

Our guide to the weather in Belfast during September

16

Average high

3

UV Index

101mm

Monthly rainfall

86%

Humidity

We've looked at the most up-to-date weather data for Belfast, covering the last 12 years up to 2024, plus we've asked our team of travel bloggers for their first-hand experiences in order to answer the most frequently asked questions about Belfast weather in September.

What's the temperature like in Belfast during September?

The temperature reaches around 16℃ during the daytime in September, falling away to 10℃ at night. The UV index will be moderate at this time of year, so not something to worry about for the average person. However, if you're going to be outside for long periods it's worth wearing a broad spectrum SPF 30+ sunscreen and UV-blocking sunglasses. Remember that bright surfaces, such as water and sand increase UV exposure.

Does it rain in Belfast during September?

On average, there will be 8 rainy days during the month, amounting to 100.9mm in total. That's a significant amount of rain. For comparison, the wettest months in the UK typically sees between 80mm and 100mm, depending on where you are. You're not likely to see a thunderstorm during your trip.

Is it windy in Belfast during September?

You're unlikely to experience any strong winds. Expect a gentle breeze that increases to moderate at times during September. With moderate air temperatures, any breeze will feel cool.

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Belfast Blog posts

From the Ireland's most popular travel bloggers

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Belfast staycation

9th August 2020 by The Daily S'elf

At a time when we’re all looking for staycation inspiration, it can be easy to overlook cities in favour of heading to the beach. But considering just about everyone else has had the same idea, now is actually a great time to find good value on hotels and eating out, especially in Northern Ireland. When looking for places to go near me, a Belfast staycation was an obvious choice - no need for an epic trek, just two hours in the car from Dublin....

Weather in Belfast

Our month-by-month guide to the weather and climate in Belfast

6.6

Belfast weather in

January
7.3

Belfast weather in

February
8.9

Belfast weather in

March
11.0

Belfast weather in

April
13.5

Belfast weather in

May
16.3

Belfast weather in

June
17.6

Belfast weather in

July
17.1

Belfast weather in

August
15.5

Belfast weather in

September
12.8

Belfast weather in

October
9.5

Belfast weather in

November
7.1

Belfast weather in

December