Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The onset of September brings a small shift in high-temperatures, falling from a tropical 33.7°C (92.7°F) in August to a warm 29.9°C (85.8°F). Viana do Alentejo observes a dramatic plunge from daytime highs in September, settling at an average low-temperature of 16.1°C (61°F).Heat index
The heat index value during September is estimated at a tropical 31°C (87.8°F). If one endures exposure and continues to be active, it might result in tiredness and heat cramps.Take into consideration that the heat index values are calculated for shade and light wind conditions. The heat index may experience an enhancement of 15 Fahrenheit (8 Celsius) degrees under direct sunlight.
Note: The heat index, also known as 'real feel' or 'felt air temperature', melds the effects of warmth and moisture to generate a feeling of heat. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. When you're directly under the sun's rays, remember that the heat index may surge by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it's vital to remain hydrated, particularly during prolonged physical activities.
Humidity
The average relative humidity in September in Viana do Alentejo, Portugal, is 53%.Rainfall
In Viana do Alentejo, during September, the rain falls for 5.1 days and regularly aggregates up to 14mm (0.55") of precipitation. In Viana do Alentejo, during the entire year, the rain falls for 95.6 days and collects up to 308mm (12.13") of precipitation.Daylight
In Viana do Alentejo, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 07:02 and sunset at 20:01. On the last day of September, sunrise is at 07:27 and sunset at 19:16 WEST.
Sunshine
In September, the average sunshine is 9.2h.UV index
The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index, 6 during September, leads to the following recommendations:
Use measures and accept sun safety conventions. Guarding against skin and eye trauma is of high priority. Stay out of direct sunlight between 10 a.m. and 4 p.m., when UV radiation is most intense, and remember that not all shade structures provide complete protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in Viana do Alentejo in September?
What is the average humidity in September in Viana do Alentejo?
How much does it rain in Viana do Alentejo in September?
How many hours of daylight does Viana do Alentejo have in September?
When are sunrise and sunset in September in Viana do Alentejo?
How many hours of sunshine does Viana do Alentejo have in September?
What is the UV index intensity in September in Viana do Alentejo?
Average temperature in September
Viana do Alentejo, Portugal
- Average high temperature in September: 29.9°C
The warmest month (with the highest average high temperature) is August (33.7°C).
The month with the lowest average high temperature is January (13.7°C).
- Average low temperature in September: 16.1°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 (5.2°C).
Average pressure in September
Viana do Alentejo, Portugal
- Average pressure in September: 1016.4mbar
The month with the highest atmospheric pressure is December (1022.8mbar).
The month with the lowest atmospheric pressure is April (1015.4mbar).
Average wind speed in September
Viana do Alentejo, Portugal
- Average wind speed in September: 9.5km/h
The windiest months (with the highest average wind speed) are February and March (12km/h).
The calmest month (with the lowest average wind speed) is September (9.5km/h).
Average humidity in September
Viana do Alentejo, Portugal
- Average humidity in September: 53%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is August (49%).
Average rainfall in September
Viana do Alentejo, Portugal
- Average rainfall in September: 14mm
The wettest month (with the highest rainfall) is April (52mm).
The driest month (with the least rainfall) is July (2mm).
Average rainfall days in September
Viana do Alentejo, Portugal
- Average rainfall days in September: 5.1 days
The month with the highest number of rainy days is March (13.8 days).
The month with the least rainy days is August (2 days).
Average daylight in September /
Average sunshine in September
Viana do Alentejo, Portugal
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 1min
The months with the most sunshine are July and August (Average sunshine: 11h and 24min).
The month with the least sunshine is January (Average sunshine: 5h and 0min).
Average sunshine days in September
Viana do Alentejo, Portugal
- Average sunshine days in September: 23.5 days
The month with the most sunshine days is July (28.8 days).
The month with the least sunshine days is April (15.3 days).
Average UV index in September
Viana do Alentejo, Portugal
- Average UV index in September: 6
The month with the highest UV index is August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Viana do Alentejo, Portugal
- Average cloud cover in September: 19
The month with the most cloud cover is January (Cloud cover 44).
The months with the least cloud cover are July and August (Cloud cover 11).
Average visibility in September
Viana do Alentejo, Portugal
- Average visibility in September: 10km
The months with the highest visibility are June, July, August and September (10km).
The months with the lowest visibility are January and April (8km).
Viana do Alentejo, Portugal
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