Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The average high-temperature decreases in December, shifting from a frosty 47.1°F (8.4°C) in November to a cold 34.7°F (1.5°C). An average low-temperature of 23.9°F (-4.5°C) is common during the nights of December.Humidity
The average relative humidity in December is 80%.Rainfall
February and December are months with the least rain when the rain falls for 7.8 days and typically aggregates up to 1.46" (37mm) of rain.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 8 days. Throughout December, 2.2" (56mm) of snow is accumulated. In Letts, during the entire year, snow falls for 40.1 days and aggregates up to 16.38" (416mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 7:12 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 4:45 pm CST.
Sunshine
In Letts, the average sunshine in December is 4.6h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for average individuals.Note: The maximum UV index of 1 during December leads to these instructions:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
What is the driest month in Letts?
How many days does it rain in December?
How much does it snow in Letts in December?
What is the month with the shortest days?
How many hours of daylight does Letts have in December?
What time are sunrise and sunset in December?
How long on average sun shines in December?
When is the lowest UV index?
How high is the UV index in December?
Average temperature in December
Letts, IA
- Average high temperature in December: 34.7°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28.4°F).
- Average low temperature in December: 23.9°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (16.3°F).
Average pressure in December
Letts, IA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Letts, IA
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in December
Letts, IA
- Average humidity in December: 80%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Letts, IA
- Average rainfall in December: 1.46"
The wettest month (with the highest rainfall) is May (5").
The driest months (with the least rainfall) are February and December (1.46").
Average rainfall days in December
Letts, IA
- Average rainfall days in December: 7.8 days
The month with the highest number of rainy days is May (19.7 days).
The months with the least rainy days are January and February (6.3 days).
Average snowfall in December
Letts, IA
- Average snowfall in December: 2.2"
The month with the highest snowfall is January (4.92").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Letts, IA
- Average snowfall days in December: 8 days
The month with the highest number of snowfall days is January (12.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Letts, IA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 4h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Letts, IA
- Average sunshine days in December: 16.8 days
The month with the most sunshine days is November (17.2 days).
The month with the least sunshine days is June (8.3 days).
Average UV index in December
Letts, IA
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Letts, IA
- Average cloud cover in December: 52
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are August and September (Cloud cover 29).
Average visibility in December
Letts, IA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Letts, Iowa, USA
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