September weather forecastPlymouth, United Kingdom

September

Weather in September

The advent of September brings a subtle change in Plymouth's weather. Pleasantness persists despite the drop in temperatures to 18.1°C (64.6°F), indicating an unhurried approach to autumn. The city undergoes a subtle transformation as greeneries display the first sign of autumnal hues. People start retreating indoors after weeks of outdoor enjoyment. The fading warmth of summer still lingers, allowing the celebration of its afterglow.

Temperature

Plymouth experiences a recorded average high-temperature of a comfortable 18.1°C (64.6°F) in September, closely aligned with August's 20°C (68°F). Plymouth experiences a consistent average temperature of 11.6°C (52.9°F) throughout the nights in September.

Rainfall

In Plymouth, during September, the rain falls for 9.9 days and regularly aggregates up to 74mm (2.91") of precipitation. In Plymouth, during the entire year, the rain falls for 142.2 days and collects up to 1007mm (39.65") of precipitation.

Sea temperature

In Plymouth, the average seawater temperature in September is 16°C (60.8°F).
Note: For the majority of people, swimming in water at 16°C (60.8°F) is not enjoyable. The challenge of controlling breathing escalates as the temperature decreases from 21°C (69.8°F) to 15°C (59°F).

Daylight

In Plymouth, the average length of the day in September is 12h and 37min.
On the first day of the month, sunrise is at 6:31 am and sunset at 8:00 pm. On the last day of September, sunrise is at 7:16 am and sunset at 6:56 pm BST.

Sunshine

In Plymouth, United Kingdom, the average sunshine in September is 5.4h.

UV index

In September, the average daily maximum UV index in Plymouth is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 4 suggests this advice:
Exercise prevention - Protecting skin and eyes from harm is required. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.

Updated: Feb 8, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

The high-temperature, in September, in Plymouth, is 18.1°C (64.6°F), while the low-temperature averages to 11.6°C (52.9°F).

In Plymouth, United Kingdom, in September, during 9.9 rainfall days, 74mm (2.91") of precipitation is typically accumulated.

In September, the average sea temperature is 16°C (60.8°F). For swimming, a surface water temperature of 16°C (60.8°F) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 21°C (69.8°F).

The average day length in September in Plymouth is 12h and 37min.

On the first day of September in Plymouth, sunrise is at 6:31 am and sunset at 8:00 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 6:56 pm BST.

In Plymouth, United Kingdom, the average sunshine duration in September is 5.4h.

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

20°C

18.1°C

14.8°C

Average low temperature

Average rainfall

Average rainfall days

10.1

9.9

14.4

Average sea temperature

Average daylight

Average sunshine

Average UV index

Average temperature in September
Plymouth, United Kingdom

Average high temperature in September: 18.1°C

The warmest month (with the highest average high temperature) is August (20°C).
The months with the lowest average high temperature are January and February (8.8°C).

Average low temperature in September: 11.6°C

The month with the highest average low temperature is August (13.4°C).
The coldest month (with the lowest average low temperature) is February (3.6°C).

Average rainfall in September
Plymouth, United Kingdom

Average rainfall in September: 73.7mm

The wettest month (with the highest rainfall) is December (118.8mm).
The driest month (with the least rainfall) is June (57.2mm).

Average rainfall days in September
Plymouth, United Kingdom

Average rainfall days in September: 9.9 days

The month with the highest number of rainy days is January (15.1 days).
The month with the least rainy days is June (8.5 days).

Average sea temperature in September
Plymouth, United Kingdom

Average sea temperature in September: 16°C

The best month for swimming (with the highest average sea temperature) is August (16.9°C).
The coldest month (with the lowest average sea temperature) is March (9.5°C).

Average daylight in September /
Average sunshine in September
Plymouth, United Kingdom

Average daylight in September: 12h and 36min

The month with the longest days is June (Average daylight: 16h and 24min).
The month with the shortest days is December (Average daylight: 8h and 6min).

Average sunshine in September: 5h and 24min

The month with the most sunshine is June (Average sunshine: 7h and 24min).
The month with the least sunshine is December (Average sunshine: 1h and 48min).

Average UV index in September
Plymouth, United Kingdom

Average UV index in September: 4

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).