Average Weather in January in Colfax California, United States
Daily high temperatures increase by 2°F, from 53°F to 55°F, rarely falling below 44°F or exceeding 65°F.
Daily low temperatures are around 41°F, rarely falling below 33°F or exceeding 49°F.
For reference, on July 29, the hottest day of the year, temperatures in Colfax typically range from 69°F to 89°F, while on December 27, the coldest day of the year, they range from 40°F to 52°F.
Average High and Low Temperature in January
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.
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 average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.
Fondi, Italy (6,188 miles away) and Fyteíes, Greece (6,558 miles) are the far-away foreign places with temperatures most similar to Colfax (view comparison).
The month of January in Colfax experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 58% throughout the month.
The clearest day of the month is January 26, with clear, mostly clear, or partly cloudy conditions 44% of the time.
For reference, on February 21, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 60%, while on July 29, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 90%.
Cloud Cover Categories in January
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Colfax, the chance of a wet day over the course of January is essentially constant, remaining around 32% throughout.
For reference, the year's highest daily chance of a wet day is 35% on February 20, and its lowest chance is 0% on July 27.
Probability of Precipitation in January
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).
To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during January in Colfax is essentially constant, remaining about 5.5 inches throughout, and rarely exceeding 12.1 inches or falling below 0.4 inches.
Average Monthly Rainfall in January
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.
Over the course of January in Colfax, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 44 minutes, implying an average daily increase of 1 minute, 27 seconds, and weekly increase of 10 minutes, 10 seconds.
The shortest day of the month is January 1, with 9 hours, 29 minutes of daylight and the longest day is January 31, with 10 hours, 13 minutes of daylight.
Hours of Daylight and Twilight in January
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.
The latest sunrise of the month in Colfax is 7:23 AM on January 5 and the earliest sunrise is 12 minutes earlier at 7:11 AM on January 31.
The earliest sunset is 4:52 PM on January 1 and the latest sunset is 32 minutes later at 5:23 PM on January 31.
Daylight saving time is observed in Colfax 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 5:38 AM and sets 14 hours, 55 minutes later, at 8:33 PM, while on December 21, the shortest day of the year, it rises at 7:19 AM and sets 9 hours, 25 minutes later, at 4:44 PM.
Sunrise & Sunset with Twilight in January
The solar day over the course of January. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The chance that a given day will be muggy in Colfax is essentially constant during January, remaining around 0% throughout.
For reference, on August 23, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in January
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Colfax is essentially constant during January, remaining within 0.1 miles per hour of 5.9 miles per hour throughout.
For reference, on December 18, the windiest day of the year, the daily average wind speed is 6.0 miles per hour, while on May 19, the calmest day of the year, the daily average wind speed is 5.2 miles per hour.
Average Wind Speed in January
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in Colfax throughout January is predominantly from the east
, with a peak proportion of 49%
on January 6
Wind Direction in January
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
The growing season in Colfax typically lasts for 10 months (306 days), from around February 20 to around December 23, rarely starting after April 7, or ending before November 20.
The month of January in Colfax is more likely than not fully outside of the growing season, with the chance that a given day is in the growing season reaching a low of 36% on January 15.
Time Spent in Various Temperature Bands and the Growing Season in January
The percentage of time spent in various temperature bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The black line is the percentage chance that a given day is within the growing season.
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
The average accumulated growing degree days in Colfax are gradually increasing during January, increasing by 44°F, from 0°F to 44°F, over the course of the month.
Growing Degree Days in January
The average growing degree days accumulated over the course of January, with 25th to 75th and 10th to 90th percentile bands.
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy in Colfax is gradually increasing during January, rising by 0.7 kWh, from 2.1 kWh to 2.8 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in January
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.
For the purposes of this report, the geographical coordinates of Colfax are 39.101 deg latitude, -120.953 deg longitude, and 2,218 ft elevation.
The topography within 2 miles of Colfax contains very significant variations in elevation, with a maximum elevation change of 1,752 feet and an average elevation above sea level of 2,199 feet. Within 10 miles contains very significant variations in elevation (3,468 feet). Within 50 miles also contains extreme variations in elevation (9,911 feet).
The area within 2 miles of Colfax is covered by shrubs (64%) and trees (36%), within 10 miles by shrubs (49%) and trees (46%), and within 50 miles by trees (44%) and shrubs (17%).
This report illustrates the typical weather in Colfax 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Colfax.
For each station, the records are corrected for the elevation difference between that station and Colfax 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 Colfax is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Colfax and a given station.
The stations contributing to this reconstruction are: Nevada County Air Park (43%, 14 kilometers, north); Auburn Municipal Airport (50%, 20 kilometers, southwest); and Blue Canyon-Nyack Airport (8%, 29 kilometers, northeast).
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.