Northern IrelandAverage 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.
Start of September
The month of September starts in Portstewart with mild temps, averaging around 18°C during the day and nights around 13°C. A few showers might pop up early in the month, but overall, it’ll stay mostly sunny and dry.
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 Portstewart 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.
In September, there is an average of 76 mm of precipitation, spread over 16 days. The wind speed is around 4 Bft, mostly coming from the Southwest.
Portstewart in September |
New York | ||
|---|---|---|---|
 Average temperature |
16°C | 27°C | |
 Max. temperature |
19°C | 31°C | |
| Min. temperature |
15°C | -5°C | |
 Total precipitation |
76 mm | 57 mm | |
| Rainy days |
16 days | 9 days | |
August
UV index
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.
Is September a good time to visit Portstewart?
Looking for sun and warm weather? September isn’t a good month to be in Portstewart. The temperatures are too low for a warm stay this month.
Temperature records
With 26°C in 2023, Portstewart 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 2°C to a highest value of 17°C.
Check out the climate of Portstewart for all months and discover the best travel time
Daily Temperature in September in Portstewart
This chart shows the average daily high and low temperatures in September for Portstewart, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in September in Portstewart
The chart below shows the average daily precipitation in September for Portstewart, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed 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 it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 16 days of precipitation 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 few years.
Total precipitation in September in Portstewart over the years
This chart shows the average precipitation in September in Portstewart, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
Daily weather in September for Portstewart
Click on any day in September to get detailed info about the usual 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
