September weather forecast
Plymouth, CA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Plymouth, California, with an average temperature varying between 57°F (13.9°C) and 85.1°F (29.5°C).

Temperature

September brings an average high-temperature of a warm 85.1°F (29.5°C), showing a slight difference from August's 90.1°F (32.3°C). Plymouth in September observes a substantial swing from the daily highs, with average nighttime temperatures of 57°F (13.9°C).

Heat index

In September, the heat index is calculated to be 84.2°F (29°C). If exposure and activity are sustained, they might cause a feeling of weariness, resulting in heat cramps.
One should consider that heat index numbers are for shaded settings and light wind. A rise of up to 15 Fahrenheit (8 Celsius) degrees in the heat index could result from direct sunlight.
Note: The heat index, also known as 'feels like' or 'real feel', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. Direct sunlight can potentially raise the heat index by 15 Fahrenheit (8 Celsius) degrees, so it's crucial to consider. Heat index values remain especially vital for babies and toddlers. Kids frequently ignore the importance of taking a break and rehydrating. Thirst is a late symptom of dehydration - thus, it is crucial to stay hydrated, especially during long-lasting physical activities.

Humidity

In September, the average relative humidity in Plymouth is 42%.

Rainfall

In Plymouth, in September, it is raining for 3 days, with typically 0.24" (6mm) of accumulated precipitation. In Plymouth, during the entire year, the rain falls for 81.8 days and collects up to 23.39" (594mm) of precipitation.

Snowfall

In Plymouth, snow does not fall in January, April through October.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:33 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:59 am and sunset at 6:47 pm PDT.

Sunshine

The average sunshine in September is 11.3h.

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 5 in September transforms into the following instructions:
Adopt protective measures - It is advised to guard against sun damage. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Boost your sun resistance with garments that are densely woven yet spacious.
Updated: Jul 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is September?

In September, in Plymouth, the average high-temperature is 85.1°F (29.5°C), and the average low-temperature is 57°F (13.9°C). The average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, in September is calculated to be 84.2°F (29°C).

What is the average humidity in September?

In Plymouth, the average relative humidity in September is 42%.

How many days does it rain in September?

In Plymouth, in September, it is raining for 3 days, with typically 0.24" (6mm) of accumulated precipitation.

When it does not snow?

January, April through October are months without snowfall.

How many hours of daylight does Plymouth have in September?

The average day length in September is 12h and 25min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:33 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:47 pm PDT.

How long on average sun shines in September?

In September, the average sunshine duration in Plymouth, California, is 11.3h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Plymouth, CA

Average temperature in September - Plymouth, CA
  • Average high temperature in September: 85.1°F

The warmest month (with the highest average high temperature) is July (91°F).
The month with the lowest average high temperature is December (52.9°F).

  • Average low temperature in September: 57°F

The month with the highest average low temperature is July (59°F).
The coldest month (with the lowest average low temperature) is December (37.9°F).

Average pressure in September
Plymouth, CA

Average pressure in September - Plymouth, CA
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Plymouth, CA

Average wind speed in September - Plymouth, CA
  • Average wind speed in September: 4mph

The windiest month (with the highest average wind speed) is February (5.7mph).
The calmest month (with the lowest average wind speed) is August (3.8mph).

Average humidity in September
Plymouth, CA

Average humidity in September - Plymouth, CA
  • Average humidity in September: 42%

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is July (40%).

Average rainfall in September
Plymouth, CA

Average rainfall in September - Plymouth, CA
  • Average rainfall in September: 0.24"

The wettest month (with the highest rainfall) is March (4.69").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in September
Plymouth, CA

Average rainfall days in September - Plymouth, CA
  • Average rainfall days in September: 3 days

The month with the highest number of rainy days is March (14.6 days).
The month with the least rainy days is August (1.5 days).

Average snowfall in September
Plymouth, CA

Average snowfall in September - Plymouth, CA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.01").
The months with the least snowfall are January, April, May, June, July, August, September and October (0").

Average snowfall days in September
Plymouth, CA

Average snowfall days in September - Plymouth, CA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (1.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Plymouth, CA

Average daylight in September / Average sunshine in September - Plymouth, CA
  • 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: 11h and 2min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).

Average sunshine days in September
Plymouth, CA

Average sunshine days in September - Plymouth, CA
  • Average sunshine days in September: 26.5 days

The month with the most sunshine days is August (28.8 days).
The month with the least sunshine days is March (15.1 days).

Average UV index in September
Plymouth, CA

Average UV index in September - Plymouth, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in September
Plymouth, CA

Average cloud cover in September - Plymouth, CA
  • Average cloud cover in September: 8

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in September
Plymouth, CA

Average visibility in September - Plymouth, CA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Plymouth, California, USA

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