September weather forecast
New Castle, CO

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Weather in September

September, the first month of the autumn in New Castle, is also an agreeable month, with an average temperature fluctuating between 43.9°F (6.6°C) and 70.9°F (21.6°C).

Temperature

The transition into September involves a small decrease in the average high-temperature, dipping slightly from a moderately hot 78.4°F (25.8°C) in August to a pleasant 70.9°F (21.6°C). New Castle measures a considerable dip from daytime highs with an average low-temperature of 43.9°F (6.6°C) during September.

Humidity

In September, the average relative humidity is 48%.

Rainfall

September is the month with the least rainfall in New Castle. Rain falls for 7.9 days and accumulates 0.51" (13mm) of precipitation.

Snowfall

June through September are months without snowfall in New Castle, Colorado.

Daylight

The average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 6:39 am and sunset at 7:40 pm. On the last day of September, in New Castle, sunrise is at 7:06 am and sunset at 6:53 pm MDT.

Sunshine

The average sunshine in September in New Castle is 11h.

UV index

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, a daily UV index of 4 turns into the following recommendations:
Undertake precautions - It is suggested to shield oneself from sunburn. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for New Castle in September?

The high-temperature, in September, in New Castle, records 70.9°F (21.6°C), while the low-temperature is 43.9°F (6.6°C).

What is the average humidity in September in New Castle?

In New Castle, the average relative humidity in September is 48%.

What is the driest month in New Castle?

September is the month with the least rainfall in New Castle. Rain falls for 7.9 days and accumulates 0.51" (13mm) of precipitation.

How much does it rain in New Castle in September?

In New Castle, Colorado, during September, the rain falls for 7.9 days and regularly aggregates up to 0.51" (13mm) of precipitation.

When it does not snow in New Castle?

In New Castle, snow does not fall in June through September.

Does it snow in New Castle in September?

In New Castle, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September in New Castle?

In New Castle, Colorado, the average day length in September is 12h and 26min.

What time are sunrise and sunset in September in New Castle?

In September, on the first day of the month, sunrise is at 6:39 am and sunset at 7:40 pm. On the last day of the month, in New Castle, Colorado, sunrise is at 7:06 am and sunset at 6:53 pm MDT.

How many hours of sunshine does New Castle have in September?

The average sunshine duration in September in New Castle is 11h.

What is the UV index intensity in September in New Castle?

In New Castle, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
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
New Castle, CO

Average temperature in September - New Castle, CO
  • Average high temperature in September: 70.9°F

The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (30.6°F).

  • Average low temperature in September: 43.9°F

The month with the highest average low temperature is July (50.4°F).
The coldest month (with the lowest average low temperature) is January (12°F).

Average pressure in September
New Castle, CO

Average pressure in September - New Castle, CO
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is May (29.93"Hg).

Average wind speed in September
New Castle, CO

Average wind speed in September - New Castle, CO
  • Average wind speed in September: 5.3mph

The windiest month (with the highest average wind speed) is June (6.2mph).
The calmest month (with the lowest average wind speed) is January (4.1mph).

Average humidity in September
New Castle, CO

Average humidity in September - New Castle, CO
  • Average humidity in September: 48%

The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is June (43%).

Average rainfall in September
New Castle, CO

Average rainfall in September - New Castle, CO
  • Average rainfall in September: 0.51"

The wettest month (with the highest rainfall) is April (1.57").
The driest month (with the least rainfall) is September (0.51").

Average rainfall days in September
New Castle, CO

Average rainfall days in September - New Castle, CO
  • Average rainfall days in September: 7.9 days

The month with the highest number of rainy days is April (14 days).
The month with the least rainy days is June (5.9 days).

Average snowfall in September
New Castle, CO

Average snowfall in September - New Castle, CO
  • Average snowfall in September: 0"

The month with the highest snowfall is February (8.74").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
New Castle, CO

Average snowfall days in September - New Castle, CO
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (13 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
New Castle, CO

Average daylight in September / Average sunshine in September - New Castle, CO
  • 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 24min).

  • Average sunshine in September: 11h and 0min

The months with the most sunshine are June, July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 6h and 6min).

Average sunshine days in September
New Castle, CO

Average sunshine days in September - New Castle, CO
  • Average sunshine days in September: 17.7 days

The month with the most sunshine days is June (20.7 days).
The month with the least sunshine days is April (11.7 days).

Average UV index in September
New Castle, CO

Average UV index in September - New Castle, CO
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in September
New Castle, CO

Average cloud cover in September - New Castle, CO
  • Average cloud cover in September: 12

The month with the most cloud cover is February (Cloud cover 39).
The months with the least cloud cover are June and September (Cloud cover 12).

Average visibility in September
New Castle, CO

Average visibility in September - New Castle, CO
  • Average visibility in September: 6mi

The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The month with the lowest visibility is January (4mi).

New Castle, Colorado, USA

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