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
September, with its high-temperature average of 70.2°F (21.2°C) and a low-temperature average of 56.8°F (13.8°C), is the warmest month.Humidity
In September, the average relative humidity is 73%.Rainfall
In Millbrae, in September, during 3.4 rainfall days, 0.16" (4mm) of precipitation is typically accumulated. In Millbrae, during the entire year, the rain falls for 81.5 days and collects up to 12.8" (325mm) of precipitation.Daylight
In Millbrae, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of September, in Millbrae, sunrise is at 7:04 am and sunset at 6:53 pm PDT.
Sunshine
The average sunshine in September is 10.9h.UV index
June through September, with an average maximum UV index of 5, are months with the highest UV index in Millbrae. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the maximum UV index of 5 transforms into these recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Frequently asked questions
What is the warmest month in Millbrae?
What are the temperatures in Millbrae in September?
What is the average humidity in September in Millbrae?
How many days does it rain in September in Millbrae?
What is the average length of the day in September in Millbrae?
When is the sunrise / sunset in September in Millbrae?
How long on average sun shines in September in Millbrae?
What is the month with the highest UV index in Millbrae?
How high is the UV index in September in Millbrae?
Average temperature in September
Millbrae, CA
- Average high temperature in September: 70.2°F
The warmest month (with the highest average high temperature) is September (70.2°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in September: 56.8°F
The month with the highest average low temperature is September (56.8°F).
The coldest month (with the lowest average low temperature) is January (47.5°F).
Average pressure in September
Millbrae, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in September
Millbrae, CA
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is September (6.1mph).
Average humidity in September
Millbrae, CA
- Average humidity in September: 73%
The month with the highest relative humidity is August (78%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Millbrae, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is February (2.44").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in September
Millbrae, CA
- Average rainfall days in September: 3.4 days
The month with the highest number of rainy days is March (12.8 days).
The months with the least rainy days are June and July (2.4 days).
Average daylight in September /
Average sunshine in September
Millbrae, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
Millbrae, CA
- Average sunshine days in September: 23.2 days
The month with the most sunshine days is July (24.6 days).
The month with the least sunshine days is March (16.3 days).
Average UV index in September
Millbrae, CA
- Average UV index in September: 5
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and December (UV index 3).
Average cloud cover in September
Millbrae, CA
- Average cloud cover in September: 15
The month with the most cloud cover is March (Cloud cover 36).
The months with the least cloud cover are July and September (Cloud cover 15).
Average visibility in September
Millbrae, 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).
Millbrae, California, USA
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