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 sea temperature 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
A subtle change in temperatures is noted as August gives way to September, with average highs reducing from a warm 83.7°F (28.7°C) to a still moderately hot 77.4°F (25.2°C). September brings Herald Harbor a consistent average low-temperature of 63.3°F (17.4°C).Humidity
In September, the average relative humidity is 75%.Rainfall
The month with the least rainfall is September, when the rain falls for 11.8 days and typically collects 1.89" (48mm) of precipitation.Snowfall
In Herald Harbor, snow does not fall in May through October.Ocean temperature
In Herald Harbor, the average seawater temperature in September is 73.6°F (23.1°C).Note: Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 73.6°F (23.1°C) water may be enjoyable. (FYI: The official water temperature required for the Olympic swimming competition is 77°F (25°C) to 82.4°F (28°C).)
Daylight
In Herald Harbor, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:36 pm. On the last day of September, sunrise is at 7:01 am and sunset at 6:50 pm EDT.
Sunshine
In Herald Harbor, the average sunshine in September is 9.2h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for average individuals.Note: In September, the maximum UV index of 5 suggests these recommendations:
Take necessary precautions - Defending against sun damage is advocated. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Attention! UV radiation is ramped up when reflecting off sand and water surfaces.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
What is the driest month?
How many days does it rain in September?
When it does not snow?
What is the water temperature in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Herald Harbor, MD
- Average high temperature in September: 77.4°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (39.6°F).
- Average low temperature in September: 63.3°F
The month with the highest average low temperature is July (70.7°F).
The coldest month (with the lowest average low temperature) is January (28.4°F).
Average pressure in September
Herald Harbor, MD
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Herald Harbor, MD
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is March (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).
Average humidity in September
Herald Harbor, MD
- Average humidity in September: 75%
The month with the highest relative humidity is May (78%).
The months with the lowest relative humidity are January, March, April and November (72%).
Average rainfall in September
Herald Harbor, MD
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is August (3.54").
The driest month (with the least rainfall) is September (1.89").
Average rainfall days in September
Herald Harbor, MD
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is November (9.4 days).
Average snowfall in September
Herald Harbor, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Herald Harbor, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Herald Harbor, MD
- Average sea temperature in September: 73.5°F
The best month for swimming (with the highest average sea temperature) is August (77.5°F).
The coldest month (with the lowest average sea temperature) is February (44.5°F).
Average daylight in September /
Average sunshine in September
Herald Harbor, MD
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 6min).
Average sunshine days in September
Herald Harbor, MD
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is May (10.8 days).
Average UV index in September
Herald Harbor, MD
- Average UV index in September: 5
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, November and December (UV index 2).
Average cloud cover in September
Herald Harbor, MD
- Average cloud cover in September: 34
The months with the most cloud cover are February and March (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 28).
Average visibility in September
Herald Harbor, MD
- 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).
Herald Harbor, Maryland, USA
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