Normal weather for Portstewart in September
It's cool to moderate in September in Portstewart with an average temperature of 16°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.
In September, there is an average of 76 mm of precipitation, spread over 10 days. The wind speed is around 4 Bft, mostly coming from the Southwest.
Looking for sun and warm weather? Then September isn’t the best time to be in Portstewart. The temperature is too low this month for a warm stay.
Portstewart in September |
London | ||
|---|---|---|---|
 Average Temperature |
16°C | 20°C | |
 High Temp |
19°C | 22°C | |
| Low Temp |
15°C | 17°C | |
 Total Precipitation |
76 mm | 44 mm | |
| Rainy Days |
10 days | 8 days | |
The UV index is a maximum of 4 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
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Start of September
The month of September starts in Portstewart with mild temperatures, averaging around 18°C during the day and nights close to 13°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Mid-September
By mid-September, the average daytime temperature drops to around 17°C, with nights close to 11°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
End of September
By the end of September, the average daytime temperature in Portstewart will be around 16°C, with nights close to 10°C. A shower might show up, but overall the weather will be dry and sunny.
Temperature records
With 26°C, Portstewart hit the highest temperature in the last 10 years in September 2023. The lowest daytime temperature in this month was 10°C in 2018. The extreme night temperatures ranged from a low of 2°C to a high of 17°C.
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Daily Temperature in September in Portstewart
This chart shows the average daily high temperatures in September in Portstewart, measured in degrees Celsius. The bottom of the chart shows the days of September. Based on historical data, it shows the average daily temperatures for this month.
Daily Precipitation in September in Portstewart
The chart below shows the average daily precipitation in September for Portstewart, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect around 10 days of rain in Portstewart.
Daily UV Index in September in Portstewart
This chart shows the average daily UV index in September in Portstewart, 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.
Temperature in September in Portstewart Over the Years
This chart shows the average temperature in September in Portstewart, measured in degrees Celsius, over the past years.
Total Precipitation in September in Portstewart Over the Years
This chart shows the average precipitation in September in Portstewart, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for Portstewart
Click on a specific day in September for detailed info on the typical weather on that day in Portstewart. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Portstewart
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Average Weather in Portstewart by Month
Click on a month below to see detailed weather info for Portstewart. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of Portstewart for all months at once
