September weather forecastBilbao, Spain
September
Weather in September
September signifies the start of fall in Bilbao as temperatures gently begin their descent while remaining above 20°C (68°F). Rainfall increases to 31mm (1.22"), though it remains relatively low compared to the city's wetter months. The changing season bestows Bilbao with a blend of late-summer warmth and early-autumn coolness. The countryside dons a warm, golden hue as the leaves start changing colors, offering picture-perfect scenic vistas. As the month progresses, the days start getting shorter, while the city captures the charm of the autumn whirl.Temperature
September's onset sees an average high-temperature of an agreeable 21.6°C (70.9°F), exhibiting a slight fluctuation from the previous month. The nights of September anticipate an average low-temperature of 15.7°C (60.3°F).Humidity
The average relative humidity in September in Bilbao, Spain, is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 14 days and accumulates 31mm (1.22") of precipitation.Snowfall
In Bilbao, snow does not fall in April through November.Sea temperature
In Bilbao, the average seawater temperature in September is 20°C (68°F).Note: For most, swimming in 20°C (68°F) is not a pleasant experience. As the temperature falls from 21°C (69.8°F) to 15°C (59°F), controlling one's breathing becomes more difficult.
Daylight
In September, the average length of the day is 12h and 30min.On the first day of September in Bilbao, sunrise is at 07:36 and sunset at 20:46. On the last day of the month, sunrise is at 08:08 and sunset at 19:54 CEST.
Sunshine
The average sunshine in September in Bilbao, Spain, is 8.3h.UV index
May through September, with an average maximum UV index of 5, are months with the highest UV index. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.Note: The maximum UV index of 5 during September translates into these guidelines:
Take necessary precautions - Defending against sun damage is advocated. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Bilbao, Spain
- Average high temperature in September: 21.6°C
The warmest month (with the highest average high temperature) is August (23.3°C).
The month with the lowest average high temperature is January (10.8°C).
- Average low temperature in September: 15.7°C
The month with the highest average low temperature is August (16.9°C).
The coldest month (with the lowest average low temperature) is February (6.5°C).
Average pressure in September
Bilbao, Spain
- Average pressure in September: 1018.4mbar
The month with the highest atmospheric pressure is December (1021.8mbar).
The month with the lowest atmospheric pressure is April (1015.6mbar).
Average wind speed in September
Bilbao, Spain
- Average wind speed in September: 10.8km/h
The windiest month (with the highest average wind speed) is February (17.2km/h).
The calmest month (with the lowest average wind speed) is August (9.9km/h).
Average humidity in September
Bilbao, Spain
- Average humidity in September: 75%
The months with the highest relative humidity are May and June (79%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Bilbao, Spain
- Average rainfall in September: 31mm
The wettest month (with the highest rainfall) is November (103mm).
The driest month (with the least rainfall) is September (31mm).
Average rainfall days in September
Bilbao, Spain
- Average rainfall days in September: 14 days
The month with the highest number of rainy days is January (18.6 days).
The month with the least rainy days is October (12.7 days).
Average snowfall in September
Bilbao, Spain
- Average snowfall in September: 0mm
The month with the highest snowfall is February (12mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Bilbao, Spain
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.2 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average sea temperature in September
Bilbao, Spain
- Average sea temperature in September: 20°C
The best month for swimming (with the highest average sea temperature) is August (21°C).
The coldest months (with the lowest average sea temperature) are February and March (12°C).
Average daylight in September /
Average sunshine in September
Bilbao, Spain
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 8h and 18min
The month with the most sunshine is July (Average sunshine: 9h and 30min).
The month with the least sunshine is November (Average sunshine: 5h and 12min).
Average sunshine days in September
Bilbao, Spain
- Average sunshine days in September: 13.4 days
The month with the most sunshine days is October (15.4 days).
The month with the least sunshine days is May (8.8 days).
Average UV index in September
Bilbao, Spain
- Average UV index in September: 5
The months with the highest UV index are May, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, March, April, November and December (UV index 3).
Average cloud cover in September
Bilbao, Spain
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are September and October (Cloud cover 34).
Average visibility in September
Bilbao, Spain
- Average visibility in September: 10km
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (10km).
The month with the lowest visibility is January (9km).
