North Ireland in september: average Weather, Temperature and Climate, Where to go?
Weather in Northern Ireland in september 2025
In this section, check out the weather forecast for the month of september for most popular cities in North Ireland. These forecasts are probabilities for september from weather reports for over 10 years. The percentage indicates the probability of having the weather mentioned.
Average weather in september in Belfast
tolerable weather
Weather at 6am
52°F
Partly Cloudy
24% of time
23%
17%
15%
Weather at 12pm
61°F
Cloudy
28% of time
25%
23%
15%
Weather at 6pm
58°F
Moderate rain at times
34% of time
24%
19%
17%
Weather at 3am
52°F
27%
20%
20%
16%
Where to go in Northern Ireland in september?
Where to go in Northern Ireland in september: destination map
perfect weather
good
tolerable
bad
very bad
Where to go in each region in september?
| County Antrim (Belfast, Ballycastle (Causeway Coast), Larne...) | 59°F to 61°F | 2 à 9 days | 58°F to 59°F | tolerable weather* |
| County Armagh (Armagh, Craigavon, Portadown...) | 61°F | 3 days | tolerable weather* | |
| County Down (Donwpatrick, Bangor, Newry...) | 59°F to 61°F | 3 à 6 days | 59°F | tolerable weather* |
| County Fermanagh (Enniskillen (Fermanagh)...) | 61°F | 5 days | bad weather | |
| County Londonderry (Derry (Londonderry), Coleraine, Limavady...) | 61°F | 1 à 7 days | 59°F | tolerable weather |
| County Tyrone (Strabane, Omagh, Dungannon...) | 61°F | 2 à 3 days | bad weather* |
Where should you go in Northern Ireland in september when it comes to the weather?
Remember:
The climate in Northern Ireland in september ranges from good to bad depending on the region and city.
You are lucky: It is not ideal 100%, but the weather in North Ireland that month is quite good in Bangor (Strangford Lough district). I allows to appreciate tours in this place. And even why not take a little time to enjoy the hotel pool!
If you do not go to spend your time in a lounger by the pool, but, for example for cultural tours or hiking, the cities of Derry (Londonderry), Donwpatrick, Belfast, Larne and Ballycastle (Causeway Coast) have a ok but correct weather for that in september. Eventually, avoid going in the cities of Enniskillen (Fermanagh) and Armagh that month because the climate is rather bad.
Climate in Northern Ireland in september
Climate in Belfast in september
In the month of september, maximum temperature is 61°F and minimum temperature is 52°F (for an average temperature of 58°F). The climate is quite cool around this city in this month, but it is livable by dressing hot. With 3.9in over 6 days, you risk getting wet slightly for your holidays. But this is pretty moderate and you will not be too bothered by it.
With proper weather, the month of september is okay (but not the best month) for traveling in that area in North Ireland.
| September | |||
| Average temperature | 58°F | ||
| Highest temperature | 61°F | ||
| Lowest temperature | 52°F | ||
| Sea temperature | 58°F | ||
| Rainfall | 3.9in | ||
| Number of days with rainfall | 6 day(s) (20%) | ||
| Humidity | 93% | ||
| Daily sunshine hours | 10 | ||
| Cloud cover | 57% | ||
| Length of day | 12:43 | ||
| Our opinion at whereandwhen.net | tolerable |
Climate in Armagh in september
In the month of september, the mean temperature in Armagh is 56°F (maximum temperature is 61°F and minimum temperature is 49°F). The climate is rather cool around this city in this month, but it is livable when dressing hot. With 2.2in over 3 days, you will experience some showers throughout your stay. But this is reasonably and you will not be too bothered by it.
With an unfavorable weather, september is not recommended month to go there in North Ireland.
| September | |||
| Average temperature | 56°F | ||
| Highest temperature | 61°F | ||
| Lowest temperature | 49°F | ||
| Rainfall | 2.2in | ||
| Number of days with rainfall | 3 day(s) (9%) | ||
| Humidity | 97% | ||
| Daily sunshine hours | 10 | ||
| Cloud cover | 68% | ||
| Length of day | 12:42 | ||
| Our opinion at whereandwhen.net | bad |
Climate in Ballycastle (Causeway Coast) in september
In the month of september, the mean temperature in Ballycastle (Causeway Coast) is 58°F (maximum temperature is 59°F and minimum temperature is 54°F). The climate is fairly fresh in this city in this month, but it is bearable by dressing cosy. With 5.2in over 9 days, rainfall can happen for your journey. But this is moderate and you will not be too bothered by it.
With proper weather, the month of september is okay (but not good time) for traveling in that area in North Ireland.
| September | |||
| Average temperature | 58°F | ||
| Highest temperature | 59°F | ||
| Lowest temperature | 54°F | ||
| Sea temperature | 58°F | ||
| Rainfall | 5.2in | ||
| Number of days with rainfall | 9 day(s) (31%) | ||
| Humidity | 89% | ||
| Daily sunshine hours | 11 | ||
| Cloud cover | 57% | ||
| Length of day | 12:43 | ||
| Our opinion at whereandwhen.net | tolerable |
Climate in Derry (Londonderry) in september
In the month of september, the mean temperature in Derry (Londonderry) is 56°F (maximum temperature is 61°F and minimum temperature is 50°F). The climate is relatively cool there in september, but it is livable by dressing cosy. With 1.7in over 1 days, rainfall can happen throughout your stay. But this is rather moderate and it is only of temporary showers.
With a correct weather, september is okay (but not the best time) for traveling in Derry (Londonderry) in North Ireland.
| September | |||
| Average temperature | 56°F | ||
| Highest temperature | 61°F | ||
| Lowest temperature | 50°F | ||
| Sea temperature | 58°F | ||
| Rainfall | 1.7in | ||
| Number of days with rainfall | 1 day(s) (5%) | ||
| Humidity | 95% | ||
| Daily sunshine hours | 10 | ||
| Cloud cover | 65% | ||
| Length of day | 12:44 | ||
| Our opinion at whereandwhen.net | tolerable |
Climate in Donwpatrick in september
In the month of september, the mean temperature in Donwpatrick is 58°F (maximum temperature is 61°F and minimum temperature is 56°F). The climate is rather cold in this location in the month of september, but it is liveable when dressing cosy. With 3in over 5 days, rainfall can happen throughout your journey. But this is pretty moderate and it is only of temporary showers.
With a correct climate, september is okay (but not good month) for traveling in that area.
| September | |||
| Average temperature | 58°F | ||
| Highest temperature | 61°F | ||
| Lowest temperature | 56°F | ||
| Sea temperature | 59°F | ||
| Rainfall | 3in | ||
| Number of days with rainfall | 5 day(s) (15%) | ||
| Humidity | 88% | ||
| Daily sunshine hours | 11 | ||
| Cloud cover | 51% | ||
| Length of day | 12:43 | ||
| Our opinion at whereandwhen.net | good |
All cities in Northern Ireland in september
| Belfast in september | tolerable weather |
| Armagh in september | bad weather |
| Ballycastle (Causeway Coast) in september | tolerable weather |
| Derry (Londonderry) in september | tolerable weather |
| Donwpatrick in september | good weather |
| Enniskillen (Fermanagh) in september | bad weather |
| Larne in september | good weather |
| Annalong in september | good weather |
| Antrim in september | tolerable weather |
| Ballyclare in september | tolerable weather |
| Ballymena in september | tolerable weather |
| Ballymoney in september | tolerable weather |
| Ballywalter in september | tolerable weather |
| Banbridge in september | tolerable weather |
| Bangor in september | good weather |
| Carrickfergus in september | good weather |
| Castlereagh in september | tolerable weather |
| Castlerock in september | tolerable weather |
| Coleraine in september | tolerable weather |
| Cookstown in september | tolerable weather |
| Craigavon in september | tolerable weather |
| Donaghadee in september | tolerable weather |
| Dromore in september | bad weather |
| Dundrum in september | good weather |
| Dungannon in september | tolerable weather |
| Glenariff in september | tolerable weather |
| Holywood in september | tolerable weather |
| Kilkeel in september | tolerable weather |
| Kircubbin in september | good weather |
| Limavady in september | tolerable weather |
Weather data for North Ireland in september:
Weather data for North Ireland in september is derived from an average of the weather forecast since 2009 in Northern Ireland. There is a margin of error and these forecasts are to be considered as general information only. The weather in Northern Ireland can vary slightly from year to year, but these predictions should limit surprises. So you can pack your bags and check when is the best time to go to Northern Ireland.