September weather forecastPenryn, CA
September
Weather in September
September, the first month of the autumn in Penryn, is still a warm month, with temperature in the range of an average high of 85.8°F (29.9°C) and an average low of 58.1°F (14.5°C).Temperature
The advent of September observes an average high-temperature of a moderately hot 85.8°F (29.9°C), nearly identical to August's 91°F (32.8°C). The average low-temperature reading in September for Penryn reflects a significant fall from the daytime highs, stabilizing at a mild 58.1°F (14.5°C).Heat index
For most parts of September, the heat index is evaluated at a tropical 86°F (30°C). Constant activity during exposure could result in a state of weariness and possibly heat cramps.Bear in mind that the heat index values are determined for shaded areas and light breezes. The heat index has the possibility to be enhanced by 15 Fahrenheit (8 Celsius) degrees when there is direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'real feel', represents the fusion of temperature and moisture in the air to suggest how warm it feels. The individual's impression of temperature can be shaped by additional aspects such as metabolic variations, physical activity, and clothing. Realize that direct exposure to sunlight can augment the felt heat, leading to a potential increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Humidity
In Penryn, the average relative humidity in September is 40%.Rainfall
In Penryn, during September, the rain falls for 2.4 days and regularly aggregates up to 0.24" (6mm) of precipitation. In Penryn, during the entire year, the rain falls for 84.8 days and collects up to 28.86" (733mm) of precipitation.Snowfall
January, April through November are months without snowfall.Daylight
In September, the average length of the day is 12h and 25min.On the first day of the month, sunrise is at 6:34 am and sunset at 7:34 pm. On the last day of September, sunrise is at 7:00 am and sunset at 6:48 pm PDT.
Sunshine
In September, the average sunshine is 11.2h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: The UV index of 5 during September leads to these advisories:
Be vigilant - Preventing sunburn is recommended. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Penryn, CA
- Average high temperature in September: 85.8°F
The warmest month (with the highest average high temperature) is July (91.9°F).
The month with the lowest average high temperature is December (53.4°F).
- Average low temperature in September: 58.1°F
The month with the highest average low temperature is July (60.6°F).
The coldest month (with the lowest average low temperature) is December (39.2°F).
Average pressure in September
Penryn, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Penryn, CA
- Average wind speed in September: 4.6mph
The windiest months (with the highest average wind speed) are February and March (5.7mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in September
Penryn, CA
- Average humidity in September: 40%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is July (38%).
Average rainfall in September
Penryn, CA
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is March (5.63").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Penryn, CA
- Average rainfall days in September: 2.4 days
The month with the highest number of rainy days is March (15.4 days).
The month with the least rainy days is July (1 days).
Average snowfall in September
Penryn, CA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.18").
The months with the least snowfall are January, April, May, June, July, August, September, October and November (0").
Average snowfall days in September
Penryn, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.6 days).
The months with the least snowfall days are January, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Penryn, CA
- Average daylight in September: 12h and 24min
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 12min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January and December (Average sunshine: 5h and 48min).
Average sunshine days in September
Penryn, CA
- Average sunshine days in September: 27.3 days
The month with the most sunshine days is July (29.6 days).
The month with the least sunshine days is March (14.6 days).
Average UV index in September
Penryn, CA
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Penryn, CA
- Average cloud cover in September: 8
The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Penryn, 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).
