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Northern IrelandThe weather in September in Belfast
It's cool to moderate in September in Belfast with an average temperature of 17°C. Temperatures this month range from a low of 15°C to a high of 19°C. At night, you can expect temperatures between 9°C and 13°C.
Looking for sun and warm weather? September isn’t a good month to be in Belfast. The temperatures are too low for a warm stay this month.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Belfast, Northern Ireland. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.
Temperature records
With 25°C in 2023, Belfast reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 10°C in 2018. The extreme nighttime temperatures ranged from a lowest recorded value of 3°C to a highest value of 17°C.
Rainfall amount
In September, there is an average of 71 mm of precipitation, spread over 9 days. The wind speed is around 4 Bft, mostly coming from the South.
Daily weather in September for Belfast
Click on any day in September to get detailed info about the usual weather on that day in Belfast. Check out the historical temperatures and precipitation over the past 10 years on this day.
September weather comparison
| Belfast | New York | |
|---|---|---|
| Average temperature | 17°C | 27°C |
| Max. temperature | 19°C | 31°C |
| Min. temperature | 9°C | -5°C |
| Total precipitation | 71 mm | 57 mm |
| Rainy days | 9 days | 9 days |
Start of September
The month of September starts in Belfast with mild temps, averaging around 18°C during the day and nights around 13°C.
Mid September
By mid-September, daytime temps drop to around 17°C, with nights around 11°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.
End of September
By the end of September, the average daytime temperature in Belfast is around 16°C, while nighttime temps are about 10°C. A shower might pop up, but overall, the weather will be dry and sunny.
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UV index
The UV index is a maximum of 5 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
Check out the climate of Belfast for all months and discover the best travel time
Temperature charts
These charts show the average temperatures in September in Belfast, Northern Ireland. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in September in Belfast
Temperature in September in Belfast over the years
Precipitation charts
These charts show the average amount of precipitation in September in Belfast, Northern Ireland. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.
Daily Precipitation in September in Belfast
Total precipitation in September in Belfast over the years
Daily UV index in September in Belfast
This chart shows the average daily UV index in September in Belfast, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Weather experiences in September in Belfast
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Average weather in Belfast by month
Click on a month below to see detailed weather info for Belfast. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.