September weather forecast
Ewa, HI

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Weather in September

September, the first month of the autumn in Ewa, is still a warm month, with an average temperature ranging between min 76.3°F (24.6°C) and max 81.5°F (27.5°C).

Temperature

August and September, with an average high-temperature of 81.5°F (27.5°C), are the warmest months.

Heat index

The heat index in September is evaluated at a hot 86°F (30°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Given the heat index, its values are aligned with shaded sites and gentle winds. Direct sunlight exposure may cause a 15 Fahrenheit (8 Celsius) degrees rise in the heat index.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a single figure representing how weather conditions feel when combining temperature and humidity. This effect is personal, shaped by the individual's physical activity and heat sensitivity, influenced by factors including wind, clothing, and metabolic variances. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Youngsters often neglect the necessity for rest and hydration. Thirst is a sign of advancing dehydration - thus the importance of maintaining hydration, specifically during long-lasting physical activities.

Humidity

January, April through June, August through November, with an average relative humidity of 74%, are the least humid months.

Rainfall

In September, the rain falls for 13.3 days. Throughout September, 0.83" (21mm) of precipitation is accumulated. In Ewa, during the entire year, the rain falls for 172.2 days and collects up to 12.72" (323mm) of precipitation.

Daylight

In Ewa, the average length of the day in September is 12h and 15min.
On the first day of September, sunrise is at 6:15 am and sunset at 6:47 pm. On the last day of the month, sunrise is at 6:23 am and sunset at 6:20 pm HST.

Sunshine

In Ewa, the average sunshine in September is 9.3h.

UV index

June through September, with an average maximum UV index of 7, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum daily UV index of 7 in September interprets into the following recommendations:
Sustain precautions and conform to sun safety norms. Preventing sunburn is necessary. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is particularly strong, noting that parasols or canopies may not offer total sun protection. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.

Frequently asked questions

What time of the year is the hottest?

August and September are characterised by peak temperatures, with an average high of 81.5°F (27.5°C).

What are September temperatures?

In Ewa, in September, the average high-temperature is 81.5°F (27.5°C), and the average low-temperature is 76.3°F (24.6°C). In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 86°F (30°C).

What is the least humid month?

January, April through June, August through November, with an average relative humidity of 74%, are the least humid months.

What is the average humidity in September?

The average relative humidity in September is 74%.

How much does it rain in September?

In Ewa, during September, the rain falls for 13.3 days and regularly aggregates up to 0.83" (21mm) of precipitation.

What is the average length of the day in September?

In September, the average day length is 12h and 15min.

When is the sunrise / sunset in September in Ewa?

On the first day of September, sunrise is at 6:15 am and sunset at 6:47 pm. On the last day of the month, sunrise is at 6:23 am and sunset at 6:20 pm HST.

How many hours of sunshine does Ewa have in September?

In Ewa, the average sunshine duration in September is 9.3h.

What are the months with the highest UV index?

The months with the highest UV index are June through September, with an average maximum UV index of 7.

What is the UV index reading in September?

The average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Ewa, HI

Average temperature in September - Ewa, HI
  • Average high temperature in September: 81.5°F

The warmest months (with the highest average high temperature) are August and September (81.5°F).
The month with the lowest average high temperature is February (74.8°F).

  • Average low temperature in September: 76.3°F

The months with the highest average low temperature are August and September (76.3°F).
The coldest month (with the lowest average low temperature) is February (69.4°F).

Average pressure in September
Ewa, HI

Average pressure in September - Ewa, HI
  • Average pressure in September: 29.97"Hg

The months with the highest atmospheric pressure are March and April (30.05"Hg).
The months with the lowest atmospheric pressure are September and October (29.97"Hg).

Average wind speed in September
Ewa, HI

Average wind speed in September - Ewa, HI
  • Average wind speed in September: 9.8mph

The windiest month (with the highest average wind speed) is July (11.9mph).
The calmest months (with the lowest average wind speed) are January and October (9.1mph).

Average humidity in September
Ewa, HI

Average humidity in September - Ewa, HI
  • Average humidity in September: 74%

The month with the highest relative humidity is December (76%).
The months with the lowest relative humidity are January, April, May, June, August, September, October and November (74%).

Average rainfall in September
Ewa, HI

Average rainfall in September - Ewa, HI
  • Average rainfall in September: 0.83"

The wettest month (with the highest rainfall) is March (1.77").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in September
Ewa, HI

Average rainfall days in September - Ewa, HI
  • Average rainfall days in September: 13.3 days

The month with the highest number of rainy days is March (18.1 days).
The month with the least rainy days is July (11.3 days).

Average daylight in September /
Average sunshine in September
Ewa, HI

Average daylight in September / Average sunshine in September - Ewa, HI
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 13h and 24min).
The month with the shortest days is December (Average daylight: 10h and 54min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 11h and 0min).
The month with the least sunshine is November (Average sunshine: 6h and 42min).

Average sunshine days in September
Ewa, HI

Average sunshine days in September - Ewa, HI
  • Average sunshine days in September: 12.2 days

The months with the most sunshine days are July and August (15.3 days).
The month with the least sunshine days is March (6.8 days).

Average UV index in September
Ewa, HI

Average UV index in September - Ewa, HI
  • Average UV index in September: 7

The months with the highest UV index are June, July, August and September (UV index 7).
The months with the lowest UV index are January, February, March, April, May, October, November and December (UV index 6).

Average cloud cover in September
Ewa, HI

Average cloud cover in September - Ewa, HI
  • Average cloud cover in September: 30

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is September (Cloud cover 30).

Average visibility in September
Ewa, HI

Average visibility in September - Ewa, HI
  • 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).

Ewa, Hawaii, USA

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