September weather forecast
Crystal Lake, CT

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Weather in September

September, the first month of the autumn in Crystal Lake, is still a warm month, with an average temperature fluctuating between 73.4°F (23°C) and 54.5°F (12.5°C).

Temperature

With the commencement of September, Crystal Lake records a moderate temperature decline, with the average high easing from August's 80.1°F (26.7°C) to a still warm 73.4°F (23°C). An average nighttime temperature of 54.5°F (12.5°C) is witnessed throughout September.

Humidity

In September, the average relative humidity is 78%.

Rainfall

The month with the least rainfall is September, when the rain falls for 7.9 days and typically collects 0.39" (10mm) of precipitation.

Snowfall

June through October are months without snowfall.

Daylight

In Crystal Lake, Connecticut, the average length of the day in September is 12h and 28min.
On the first day of September, sunrise is at 6:15 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:32 pm EDT.

Sunshine

In September, the average sunshine is 8.5h.

UV index

In Crystal Lake, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: In September, a daily UV index of 4 turns into the following recommendations:
Undertake precautions - Guarding against sun damage is counselled. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. Experience reduced UV exposure by about half when donning a wide-brim hat.
Updated: Jul 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Crystal Lake in September?

The high-temperature, in September, in Crystal Lake, is 73.4°F (23°C), while the low-temperature averages to 54.5°F (12.5°C). In July, the average heat index (a.k.a. 'feels like', 'real feel'), which factors the actual air temperature with the relative humidity, is computed to be 87.8°F (31°C).

What is the average humidity in September?

In September, the average relative humidity is 78%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 7.9 days and typically collects 0.39" (10mm) of precipitation.

How much does it rain in Crystal Lake in September?

In Crystal Lake, in September, it is raining for 7.9 days, with typically 0.39" (10mm) of accumulated precipitation.

When it does not snow in Crystal Lake?

In Crystal Lake, snow does not fall in June through October.

How many hours of daylight does Crystal Lake have in September?

The average day length in September is 12h and 28min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:15 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:32 pm EDT.

How many hours of sunshine does Crystal Lake have in September?

The average sunshine duration in September is 8.5h.

What is the UV index intensity in September?

In Crystal Lake, Connecticut, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
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
Crystal Lake, CT

Average temperature in September - Crystal Lake, CT
  • Average high temperature in September: 73.4°F

The warmest month (with the highest average high temperature) is July (82.2°F).
The month with the lowest average high temperature is January (32.4°F).

  • Average low temperature in September: 54.5°F

The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in September
Crystal Lake, CT

Average pressure in September - Crystal Lake, CT
  • Average pressure in September: 30.06"Hg

The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Crystal Lake, CT

Average wind speed in September - Crystal Lake, CT
  • Average wind speed in September: 5.8mph

The windiest months (with the highest average wind speed) are January and March (8.2mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).

Average humidity in September
Crystal Lake, CT

Average humidity in September - Crystal Lake, CT
  • Average humidity in September: 78%

The month with the highest relative humidity is February (80%).
The month with the lowest relative humidity is April (71%).

Average rainfall in September
Crystal Lake, CT

Average rainfall in September - Crystal Lake, CT
  • Average rainfall in September: 0.39"

The wettest months (with the highest rainfall) are May, June and July (1.1").
The driest month (with the least rainfall) is September (0.39").

Average rainfall days in September
Crystal Lake, CT

Average rainfall days in September - Crystal Lake, CT
  • Average rainfall days in September: 7.9 days

The month with the highest number of rainy days is June (12.1 days).
The months with the least rainy days are January and February (5.5 days).

Average snowfall in September
Crystal Lake, CT

Average snowfall in September - Crystal Lake, CT
  • Average snowfall in September: 0"

The month with the highest snowfall is February (1.5").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in September
Crystal Lake, CT

Average snowfall days in September - Crystal Lake, CT
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (6.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Crystal Lake, CT

Average daylight in September / Average sunshine in September - Crystal Lake, CT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 8h and 3min

The months with the most sunshine are July and August (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in September
Crystal Lake, CT

Average sunshine days in September - Crystal Lake, CT
  • Average sunshine days in September: 19.8 days

The month with the most sunshine days is January (21.9 days).
The month with the least sunshine days is June (15.7 days).

Average UV index in September
Crystal Lake, CT

Average UV index in September - Crystal Lake, CT
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in September
Crystal Lake, CT

Average cloud cover in September - Crystal Lake, CT
  • Average cloud cover in September: 39

The months with the most cloud cover are February and March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 34).

Average visibility in September
Crystal Lake, CT

Average visibility in September - Crystal Lake, CT
  • Average visibility in September: 5mi

The months with the highest visibility are January, March, April, October, November and December (6mi).
The months with the lowest visibility are February, May, June, July, August and September (5mi).

Crystal Lake, Connecticut, USA

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