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 snowfall in September
- Average snowfall 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
September
Weather in September
Temperature
With the arrival of September, Welwyn's average high-temperature registers at a comfortable 18.5°C (65.3°F), indicating a subtle variation from the previous month. An average low-temperature of 10.9°C (51.6°F) marks the month of September in Welwyn.Humidity
In Welwyn, the average relative humidity in September is 78%.Rainfall
The month with the least rainfall is September, when the rain falls for 10.5 days and typically collects 15mm (0.59") of precipitation.Snowfall
April through October are months without snowfall in Welwyn.Daylight
In Welwyn, United Kingdom, the average length of the day in September is 12h and 39min.On the first day of September in Welwyn, sunrise is at 6:13 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:40 pm BST.
Sunshine
In September, the average sunshine in Welwyn is 7.2h.UV index
In September, the average daily maximum UV index in Welwyn is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Exercise prevention - Protecting skin and eyes from harm is required. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Welwyn?
What is the average humidity in September in Welwyn?
What is the driest month in Welwyn?
How much does it rain in Welwyn in September?
When it does not snow in Welwyn?
How many hours of daylight does Welwyn have in September?
When are sunrise and sunset in September in Welwyn?
How many hours of sunshine does Welwyn have in September?
What is the UV index intensity in September in Welwyn?
Average temperature in September
Welwyn, United Kingdom
- Average high temperature in September: 18.5°C
The warmest month (with the highest average high temperature) is July (21.4°C).
The month with the lowest average high temperature is January (6.3°C).
- Average low temperature in September: 10.9°C
The month with the highest average low temperature is August (13.3°C).
The coldest month (with the lowest average low temperature) is January (1.6°C).
Average pressure in September
Welwyn, United Kingdom
- Average pressure in September: 1016.7mbar
The months with the highest atmospheric pressure are May and September (1016.7mbar).
The month with the lowest atmospheric pressure is November (1010.3mbar).
Average wind speed in September
Welwyn, United Kingdom
- Average wind speed in September: 13.2km/h
The windiest month (with the highest average wind speed) is February (18.3km/h).
The calmest month (with the lowest average wind speed) is July (12.9km/h).
Average humidity in September
Welwyn, United Kingdom
- Average humidity in September: 78%
The month with the highest relative humidity is December (90%).
The month with the lowest relative humidity is August (75%).
Average rainfall in September
Welwyn, United Kingdom
- Average rainfall in September: 15mm
The wettest month (with the highest rainfall) is June (36mm).
The driest month (with the least rainfall) is September (15mm).
Average rainfall days in September
Welwyn, United Kingdom
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is July (16.6 days).
The month with the least rainy days is September (10.5 days).
Average snowfall in September
Welwyn, United Kingdom
- Average snowfall in September: 0mm
The month with the highest snowfall is February (16mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days in September
Welwyn, United Kingdom
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Welwyn, United Kingdom
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 36min).
The month with the shortest days is December (Average daylight: 7h and 54min).
- Average sunshine in September: 7h and 1min
The months with the most sunshine are July and August (Average sunshine: 7h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).
Average sunshine days in September
Welwyn, United Kingdom
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is September (16.5 days).
The month with the least sunshine days is July (11.1 days).
Average UV index in September
Welwyn, United Kingdom
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Welwyn, United Kingdom
- Average cloud cover in September: 48
The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 48).
Average visibility in September
Welwyn, United Kingdom
- Average visibility in September: 9km
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
