Temperatures in September
It's cool to moderate in September in Gwynedd with an average temperature of 17°C. Temperatures this month range from a low of 16°C to a high of 20°C. At night, you can expect temperatures between 9°C and 13°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Gwynedd in September. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of September
The month of September starts in Gwynedd with mild temperatures, averaging around 19°C during the day and nights close to 12°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 18°C, with nights close to 12°C. During this part of the month, you can expect regular precipitation, but there’ll also be some sunny days.
End of September
By the end of September, the average daytime temperature in Gwynedd will be around 17°C, with nights close to 11°C. There’s regular precipitation, but with a bit of luck, you’ll also get some dry and sunny days.
Discover cheap holidays to Gwynedd 
Precipitation in September
In September, there is an average of 105 mm of precipitation, spread over 15 days. The wind speed is around 5 Bft, mostly coming from the South.
The average precipitation chance is 49% per day this month. Though it seems average, the weather’s variable. Some days have higher, others lower precipitation chances.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for Gwynedd. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Gwynedd in September |
London | ||
|---|---|---|---|
 Average Temperature |
17°C | 20°C | |
 High Temp |
20°C | 22°C | |
| Low Temp |
16°C | 17°C | |
 Total Precipitation |
105 mm | 44 mm | |
| Rainy Days |
15 days | 8 days | |
August
UV index
The UV index is a maximum of 6 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is September a good time to visit Gwynedd?
Looking for sun and warm weather? Then September isn’t the best time to be in Gwynedd. The temperature is too low this month for a warm stay.
Temperature records for Gwynedd in September
With 28°C, Gwynedd hit the highest temperature in the last 10 years in September 2021. The lowest daytime temperature in this month was 11°C in 2020. The extreme night temperatures ranged from a low of 1°C to a high of 18°C.
Check out the climate of Gwynedd for all months and discover the best travel time
Plan your next holiday
Don’t miss the best holiday deals for Gwynedd and see what our partners have for you.
Daily Temperature in September in Gwynedd
This chart shows the average daily temperatures, both day and night, for each day in September in Gwynedd, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in Gwynedd
The chart below shows the average daily precipitation in September for Gwynedd, 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 15 days of rain in Gwynedd.
Daily UV Index in September in Gwynedd
This chart shows the average daily UV index in September in Gwynedd, 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 Gwynedd Over the Years
This chart shows the average temperature in September in Gwynedd, measured in degrees Celsius, over the past years.
Total Precipitation in September in Gwynedd Over the Years
This chart shows the average precipitation in September in Gwynedd, 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 Gwynedd
Click on a specific day in September for detailed info on the typical weather on that day in Gwynedd. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Gwynedd
Have you been to Gwynedd in September?
Share your weather experience in September in Gwynedd.
Average Weather in Gwynedd by Month
Click on a month below to see detailed weather info for Gwynedd. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
