January Weather in Grabouw South AfricaDaily high temperatures are around 77°F, rarely falling below 69°F or exceeding 86°F. The highest daily average high temperature is 78°F on January 27. Daily low temperatures are around 59°F, rarely falling below 53°F or exceeding 63°F. The highest daily average low temperature is 59°F on January 29. For reference, on January 26, the hottest day of the year, temperatures in Grabouw typically range from 59°F to 78°F, while on July 10, the coldest day of the year, they range from 42°F to 60°F. 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. Monte Patria, Chile (5,072 miles away) and São Francisco de Paula, Brazil (4,024 miles) are the far-away foreign places with temperatures most similar to Grabouw (view comparison). CloudsThe month of January in Grabouw experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 18% to 13%. The clearest day of the month is January 30, with clear, mostly clear, or partly cloudy conditions 87% of the time. For reference, on May 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 44%, while on February 10, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 88%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Grabouw, the chance of a wet day over the course of January is gradually decreasing, starting the month at 11% and ending it at 7%. For reference, the year's highest daily chance of a wet day is 27% on June 15, and its lowest chance is 7% on February 14. RainfallTo 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 Grabouw is essentially constant, remaining about 0.7 inches throughout, and rarely exceeding 2.1 inches or falling below -0.0 inches. SunOver the course of January in Grabouw, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 36 minutes, implying an average daily decrease of 1 minute, 12 seconds, and weekly decrease of 8 minutes, 27 seconds. The shortest day of the month is January 31, with 13 hours, 47 minutes of daylight and the longest day is January 1, with 14 hours, 23 minutes of daylight. The earliest sunrise of the month in Grabouw is 5:35 AM on January 1 and the latest sunrise is 28 minutes later at 6:03 AM on January 31. The latest sunset is 7:59 PM on January 7 and the earliest sunset is 9 minutes earlier at 7:50 PM on January 31. Daylight saving time is not observed in Grabouw during 2024. For reference, on December 21, the longest day of the year, the Sun rises at 5:29 AM and sets 14 hours, 26 minutes later, at 7:55 PM, while on June 20, the shortest day of the year, it rises at 7:49 AM and sets 9 hours, 52 minutes later, at 5:41 PM. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for January 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
HumidityWe 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 Grabouw is essentially constant during January, remaining within 1% of 2% throughout. For reference, on February 14, the muggiest day of the year, there are muggy conditions 3% of the time, while on May 4, the least muggy day of the year, there are muggy conditions 0% of the time. WindThis 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 Grabouw is essentially constant during January, remaining within 0.1 miles per hour of 12.0 miles per hour throughout. For reference, on January 24, the windiest day of the year, the daily average wind speed is 12.1 miles per hour, while on May 2, the calmest day of the year, the daily average wind speed is 9.6 miles per hour. The highest daily average wind speed during January is 12.1 miles per hour on January 24. The hourly average wind direction in Grabouw throughout January is predominantly from the south, with a peak proportion of 47% on January 8. Water TemperatureGrabouw is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water. The average surface water temperature in Grabouw is essentially constant during January, remaining around 67°F throughout. Growing SeasonDefinitions 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 Grabouw typically lasts for 11 months (345 days), from around July 23 to around July 3, rarely starting after August 26, or ending before May 31. The month of January in Grabouw is reliably fully 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 Grabouw are rapidly increasing during January, increasing by 518°F, from 1,552°F to 2,070°F, over the course of the month. Solar EnergyThis 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 Grabouw is essentially constant during January, remaining within 0.2 kWh of 8.4 kWh throughout. The highest average daily incident shortwave solar energy during January is 8.6 kWh on January 4. TopographyFor the purposes of this report, the geographical coordinates of Grabouw are -34.152 deg latitude, 19.015 deg longitude, and 1,089 ft elevation. The topography within 2 miles of Grabouw contains significant variations in elevation, with a maximum elevation change of 696 feet and an average elevation above sea level of 1,085 feet. Within 10 miles contains significant variations in elevation (5,203 feet). Within 50 miles also contains extreme variations in elevation (6,663 feet). The area within 2 miles of Grabouw is covered by cropland (90%), within 10 miles by cropland (53%) and shrubs (39%), and within 50 miles by water (43%) and cropland (29%). Data SourcesThis report illustrates the typical weather in Grabouw, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere is only a single weather station, Cape Town International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Grabouw. At a distance of 43 kilometers from Grabouw, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records. The station records are corrected for the elevation difference between the station and Grabouw according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations. Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis. Other DataAll data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports and weather stations are provided by AskGeo.com . Maps are © OpenStreetMap contributors. DisclaimerThe 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. Please review our full terms contained on our Terms of Service page. |