Fall Weather in Ontario United StatesDaily high temperatures decrease by 45°F, from 86°F to 41°F, rarely falling below 30°F or exceeding 94°F. Daily low temperatures decrease by 27°F, from 54°F to 27°F, rarely falling below 15°F or exceeding 63°F. For reference, on July 25, the hottest day of the year, temperatures in Ontario typically range from 62°F to 93°F, while on December 31, the coldest day of the year, they range from 22°F to 34°F. The figure below shows you a compact characterization of the hourly average fall temperatures. 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. Gorobinci, Macedonia (5,984 miles away); Arguvan, Turkey (6,518 miles); and Pasragad Branch, Iran (6,923 miles) are the far-away foreign places with temperatures most similar to Ontario (view comparison). CloudsThe fall in Ontario experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 23% to 58%. The clearest day of the fall is September 2, with clear, mostly clear, or partly cloudy conditions 77% of the time. For reference, on January 11, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 60%, while on July 27, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 84%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Ontario, the chance of a wet day over the course of the fall is very rapidly increasing, starting the season at 6% and ending it at 24%. For reference, the year's highest daily chance of a wet day is 24% on November 30, and its lowest chance is 3% on July 28. Over the course of the fall in Ontario, the chance of a day with only rain increases from 6% to 17%, the chance of a day with mixed snow and rain increases from 0% to 4%, and the chance of a day with only snow increases from 0% to 3%. RainfallTo show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day rainfall during the fall in Ontario is increasing, starting the season at 0.3 inches, when it rarely exceeds 0.9 inches or falls below -0.0 inches, and ending the season at 1.0 inches, when it rarely exceeds 2.1 inches or falls below 0.2 inches. SnowfallAs with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day snowfall during the fall in Ontario is increasing, starting the season at -0.0 inches, when it rarely exceeds -0.0 inches or falls below -0.0 inches, and ending the season at 2.8 inches, when it rarely exceeds 7.5 inches. SunOver the course of the fall in Ontario, the length of the day is very rapidly decreasing. From the start to the end of the season, the length of the day decreases by 4 hours, 2 minutes, implying an average daily decrease of 2 minutes, 41 seconds, and weekly decrease of 18 minutes, 49 seconds. The shortest day of the fall is November 30, with 9 hours, 9 minutes of daylight and the longest day is September 1, with 13 hours, 11 minutes of daylight. The earliest sunrise of the fall in Ontario is 7:11 AM on September 1 and the latest sunrise is 1 hour, 15 minutes later at 8:26 AM on November 2. The latest sunset is 8:22 PM on September 1 and the earliest sunset is 3 hours, 11 minutes earlier at 5:11 PM on November 30. Daylight saving time (DST) starts at 1:00 AM on November 3, 2024, shifting sunrise and sunset to be an hour later. For reference, on June 20, the longest day of the year, the Sun rises at 6:04 AM and sets 15 hours, 30 minutes later, at 9:34 PM, while on December 21, the shortest day of the year, it rises at 8:19 AM and sets 8 hours, 53 minutes later, at 5:12 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 the fall of 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 Ontario is essentially constant during the fall, remaining around 0% throughout. For reference, on August 2, the muggiest day of the year, there are muggy conditions 0% of the time, while on September 22, 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 Ontario is essentially constant during the fall, remaining within 0.2 miles per hour of 5.9 miles per hour throughout. For reference, on April 10, the windiest day of the year, the daily average wind speed is 7.3 miles per hour, while on January 10, the calmest day of the year, the daily average wind speed is 5.6 miles per hour. The wind direction in Ontario during the fall is predominantly out of the north from September 1 to November 2 and the east from November 2 to November 30. 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 Ontario typically lasts for 5.6 months (170 days), from around April 25 to around October 12, rarely starting before April 3 or after May 15, and rarely ending before September 23 or after October 31. During the fall in Ontario, the chance that a given day is within the growing season is very rapidly decreasing falling from 100% to -0% over the course of the 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 Ontario are rapidly increasing during the fall, increasing by 574°F, from 2,563°F to 3,137°F, over the course of the season. 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 Ontario is very rapidly decreasing during the fall, falling by 4.5 kWh, from 6.2 kWh to 1.7 kWh, over the course of the season. TopographyFor the purposes of this report, the geographical coordinates of Ontario are 44.027 deg latitude, -116.963 deg longitude, and 2,149 ft elevation. The topography within 2 miles of Ontario is essentially flat, with a maximum elevation change of 82 feet and an average elevation above sea level of 2,159 feet. Within 10 miles is essentially flat (945 feet). Within 50 miles contains very significant variations in elevation (6,135 feet). The area within 2 miles of Ontario is covered by artificial surfaces (50%), cropland (26%), and shrubs (23%), within 10 miles by cropland (65%) and grassland (19%), and within 50 miles by shrubs (55%) and grassland (20%). Data SourcesThis report illustrates the typical weather in Ontario, 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 are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Ontario. For each station, the records are corrected for the elevation difference between that station and Ontario 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 Ontario is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Ontario and a given station. The stations contributing to this reconstruction are:
To get a sense of how much these sources agree with each other, you can view a comparison of Ontario and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data. 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. |