Average Weather In December For South Bend, Indiana, USA

Location

This report describes the typical weather at the South Bend (South Bend, Indiana, United States) weather station over the course of an average December. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.

South Bend, Indiana has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by croplands (73%), forests (16%), built-up areas (4%), oceans and seas (4%), and grasslands (3%).

Temperature

The month of December is characterized by falling daily high temperatures, with daily highs decreasing from 41°F to 33°F over the course of the month, exceeding 54°F or dropping below 19°F only one day in ten.

Daily High and Low Temperature in December

The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Daily low temperatures range from 20°F to 28°F, falling below 5°F or exceeding 39°F only one day in ten.

Fraction of Time Spent in Various Temperature Bands in December

The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Sun

Over the course of December, the length of the day is essentially constant. The shortest day of the month is December 25 with 9:09 hours of daylight; the longest day is December 1 with 9:23 hours of daylight.

Daily Hours of Daylight and Twilight in December

The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.

The earliest sunrise is at 7:53am on December 1; the latest sunset is at 5:25pm on December 31; the latest sunrise is at 8:13am on December 31; the earliest sunset is at 5:14pm on December 7.

Daylight savings time is observed in 2012 but it neither starts nor ends in December, so the entire month is in standard time.

Daily Sunrise & Sunset with Twilight and Daylight Savings Time in December

The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight savings time are indicated by the "DST" labels.

Clouds

The median cloud cover is 99% (overcast) and does not vary substantially over the course of the month.

Median Cloud Cover in December

The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

On December 16, a representative day, the sky is clear or mostly clear 22% of the time, partly cloudy 8% of the time, and mostly cloudy or overcast 71% of the time.

Cloud Cover Types in December

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around December 30, occurring in 73% of days. Precipitation is least likely around December 1, occurring in 65% of days.

Probability of Precipitation at Some Point in the Day in December

The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

Throughout December, the most common forms of precipitation are light snow, light rain, and moderate snow.

Light snow is the most severe precipitation observed during 53% of those days with precipitation. It is most likely around December 31, when it is observed during 44% of all days.

Light rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around December 1, when it is observed during 15% of all days.

Moderate snow is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around December 31, when it is observed during 10% of all days.

Types of Precipitation Throughout December

Relative frequency of various types of precipitation over the course of a typical December.

Snow

The likelihood of snow falling is highest around December 31, occurring in 57% of days.

Probability of Snow Fall Being Reported in a Given Day in December

Probability that snow will be reported at least once in a given day.

Accumulation at this location in December is just more likely than not. The chances of there being snow on the ground are highest around December 31, occurring 59% of the time.

Chance of at Least Some Snow on the Ground in December

The probability that there is snow on the ground.

The snow is typically at its deepest on December 31, with a median depth of 3.6"; the depth exceeds 10.4" only one year out of ten.

Snow Depth When there is Snow on the Ground in December

The median depth of snow during times when there is at least some snow on the ground, with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Humidity

The relative humidity typically ranges from 63% (mildly humid) to 91% (very humid) over the course of a typical December, rarely dropping below 47% (comfortable) and reaching as high as 100% (very humid).

The air is driest around December 1, at which time the relative humidity drops below 72% (humid) three days out of four; it is most humid around December 21, rising above 87% (very humid) three days out of four.

Relative Humidity in December

The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew Point

Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.

Over the course of a typical December, the dew point typically varies from 15°F (dry) to 33°F (dry) and is rarely below -2°F (dry) or above 48°F (dry).

Dew Point in December

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind

Over the course of December typical wind speeds vary from 4 mph to 17 mph (light breeze to moderate breeze), rarely exceeding 24 mph (fresh breeze).

The highest average wind speed of 11 mph (gentle breeze) occurs around December 7, at which time the average daily maximum wind speed is 17 mph (moderate breeze).

The lowest average wind speed of 10 mph (gentle breeze) occurs around December 21, at which time the average daily maximum wind speed is 16 mph (moderate breeze).

Wind Speed in December

The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
The wind is most often out of the south west (19% of the time), south (16% of the time), north west (12% of the time), west (11% of the time), and north (11% of the time).

Wind Directions in December

The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Fraction of Time Spent with Various Wind Directions in December

The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.