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 onset of December brings a small change in high-temperatures, falling from a frosty 49.1°F (9.5°C) in November to a cold 35.2°F (1.8°C). In Siam, December is marked by an average low-temperature of 22.8°F (-5.1°C).Humidity
The average relative humidity in December is 78%.Rainfall
In December, the rain falls for 4.3 days. Throughout December, 0.59" (15mm) of precipitation is accumulated. In Siam, during the entire year, the rain falls for 114.9 days and collects up to 18.39" (467mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 4.5 days. Throughout December, 0.91" (23mm) of snow is accumulated. Throughout the year, in Siam, there are 25.2 snowfall days, and 7.4" (188mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:24 am and sunset at 4:53 pm. On the last day of December, sunrise is at 7:43 am and sunset at 5:02 pm CST.
Sunshine
In Siam, the average sunshine in December is 5h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 2 during December translates into the following directions:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
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?
How much does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Siam have in December?
When is the sunrise / sunset in December?
How long on average sun shines in December?
What are the months with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Siam, IA
- Average high temperature in December: 35.2°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (31.1°F).
- Average low temperature in December: 22.8°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (17.2°F).
Average pressure in December
Siam, IA
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in December
Siam, IA
- Average wind speed in December: 9.5mph
The windiest month (with the highest average wind speed) is March (10.3mph).
The calmest month (with the lowest average wind speed) is July (6.7mph).
Average humidity in December
Siam, IA
- Average humidity in December: 78%
The month with the highest relative humidity is January (80%).
The month with the lowest relative humidity is October (69%).
Average rainfall in December
Siam, IA
- Average rainfall in December: 0.59"
The wettest month (with the highest rainfall) is June (3.39").
The driest month (with the least rainfall) is February (0.43").
Average rainfall days in December
Siam, IA
- Average rainfall days in December: 4.3 days
The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is February (3.4 days).
Average snowfall in December
Siam, IA
- Average snowfall in December: 0.91"
The month with the highest snowfall is January (2.17").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Siam, IA
- Average snowfall days in December: 4.5 days
The month with the highest number of snowfall days is January (7.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Siam, IA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 5h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in December
Siam, IA
- Average sunshine days in December: 22 days
The month with the most sunshine days is November (22.5 days).
The month with the least sunshine days is June (12.3 days).
Average UV index in December
Siam, IA
- Average UV index in December: 2
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, November and December (UV index 2).
Average cloud cover in December
Siam, IA
- Average cloud cover in December: 45
The month with the most cloud cover is January (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 27).
Average visibility in December
Siam, IA
- Average visibility in December: 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).
Siam, Iowa, USA
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