Average Weather in January in Jefferson Iowa, United States
Daily high temperatures are around 31°F, rarely falling below 13°F or exceeding 47°F. The lowest daily average high temperature is 30°F on January 15.
Daily low temperatures are around 15°F, rarely falling below -5°F or exceeding 31°F. The lowest daily average low temperature is 14°F on January 22.
For reference, on July 18, the hottest day of the year, temperatures in Jefferson typically range from 65°F to 85°F, while on January 22, the coldest day of the year, they range from 14°F to 31°F.
Average High and Low Temperature in January
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on January. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in January
The month of January in Jefferson experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 54% throughout the month.
The clearest day of the month is January 28, with clear, mostly clear, or partly cloudy conditions 47% of the time.
For reference, on December 29, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on July 28, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 71%.
Cloud Cover Categories in January
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Jefferson, the chance of a wet day over the course of January is essentially constant, remaining around 9% throughout.
For reference, the year's highest daily chance of a wet day is 43% on June 7, and its lowest chance is 8% on January 11.
Over the course of January in Jefferson, the chance of a day with only rain remains an essentially constant 2% throughout, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 5% throughout.
Probability of Precipitation in January
The average sliding 31-day rainfall during January in Jefferson is essentially constant, remaining about 0.3 inches throughout, and rarely exceeding 0.9 inches.
The lowest average 31-day accumulation is 0.2 inches on January 23.
Average Monthly Rainfall in January
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. As with rainfall, we consider the liquid-equivalent snowfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day liquid-equivalent snowfall during January in Jefferson is essentially constant, remaining about 0.3 inches throughout, and rarely exceeding 0.8 inches or falling to 0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in January
Over the course of January in Jefferson, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 49 minutes, implying an average daily increase of 1 minute, 37 seconds, and weekly increase of 11 minutes, 21 seconds.
The shortest day of the month is January 1, with 9 hours, 11 minutes of daylight and the longest day is January 31, with 9 hours, 60 minutes of daylight.
Hours of Daylight and Twilight in January
The latest sunrise of the month in Jefferson is 7:45 AM on January 4 and the earliest sunrise is 15 minutes earlier at 7:31 AM on January 31.
The earliest sunset is 4:56 PM on January 1 and the latest sunset is 34 minutes later at 5:31 PM on January 31.
Daylight saving time is observed in Jefferson during 2018, but it neither starts nor ends during January, so the entire month is in standard time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:42 AM and sets 15 hours, 15 minutes later, at 8:56 PM, while on December 21, the shortest day of the year, it rises at 7:42 AM and sets 9 hours, 7 minutes later, at 4:49 PM.
Sunrise & Sunset with Twilight in January
The chance that a given day will be muggy in Jefferson is essentially constant during January, remaining around 0% throughout.
For reference, on July 21, the muggiest day of the year, there are muggy conditions 55% of the time, while on November 8, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in January
The average hourly wind speed in Jefferson is essentially constant during January, remaining within 0.1 miles per hour of 12.2 miles per hour throughout.
For reference, on April 12, the windiest day of the year, the daily average wind speed is 13.2 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 8.3 miles per hour.
Average Wind Speed in January
Wind Direction in January
The growing season in Jefferson typically lasts for 5.8 months (178 days), from around April 18 to around October 12, rarely starting before March 31 or after May 6, and rarely ending before September 25 or after October 30.
The month of January in Jefferson is reliably fully outside of the growing season.
Time Spent in Various Temperature Bands and the Growing Season in January
The average accumulated growing degree days in Jefferson are essentially constant during January, remaining within 1°F of 1°F throughout.
Growing Degree Days in January
The average daily incident shortwave solar energy in Jefferson is gradually increasing during January, rising by 0.6 kWh, from 1.9 kWh to 2.5 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in January
For the purposes of this report, the geographical coordinates of Jefferson are 42.015 deg latitude, -94.377 deg longitude, and 1,047 ft elevation.
The topography within 2 miles of Jefferson contains only modest variations in elevation, with a maximum elevation change of 112 feet and an average elevation above sea level of 1,042 feet. Within 10 miles also contains only modest variations in elevation (276 feet). Within 50 miles contains only modest variations in elevation (801 feet).
The area within 2 miles of Jefferson is covered by cropland (83%) and artificial surfaces (15%), within 10 miles by cropland (98%), and within 50 miles by cropland (94%).
This report illustrates the typical weather in Jefferson year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Jefferson.
For each station, the records are corrected for the elevation difference between that station and Jefferson according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Jefferson is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Jefferson and a given station.
The stations contributing to this reconstruction are: Perry Municipal Airport (40%, 28 kilometers, southeast); Arthur N Neu Airport (28%, 34 kilometers, west); Boone Municipal Airport (20%, 44 kilometers, east); and Fort Dodge Municipal Airport (12%, 62 kilometers, north).
Time zones for aiports and weather stations are provided by AskGeo.com .