Daily high temperatures are around 78°F, rarely falling below 70°F or exceeding 85°F.
Daily low temperatures decrease by 6°F, from 63°F to 57°F, rarely falling below 49°F or exceeding 67°F.
For reference, on May 10, the hottest day of the year, temperatures in Arroyo Seco typically range from 64°F to 89°F, while on January 7, the coldest day of the year, they range from 48°F to 74°F.
Average High and Low Temperature in October
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 October. 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.
The month of October in Arroyo Seco experiences very rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 70% to 52%.
The clearest day of the month is October 31, with clear, mostly clear, or partly cloudy conditions 48% of the time.
For reference, on September 16, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 76%, while on May 16, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 65%.
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Arroyo Seco, the chance of a wet day over the course of October is very rapidly decreasing, starting the month at 38% and ending it at 18%.
For reference, the year's highest daily chance of a wet day is 52% on July 2, and its lowest chance is 7% on December 26.
Probability of Precipitation in October
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 October in Arroyo Seco is very rapidly decreasing, starting the month at 4.5 inches, when it rarely exceeds 7.9 inches or falls below 1.6 inches, and ending the month at 1.6 inches, when it rarely exceeds 3.5 inches or falls below 0.2 inches.
Average Monthly Rainfall in October
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 October in Arroyo Seco, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 35 minutes, implying an average daily decrease of 1 minute, 10 seconds, and weekly decrease of 8 minutes, 11 seconds.
The shortest day of the month is October 31, with 11 hours, 21 minutes of daylight and the longest day is October 1, with 11 hours, 56 minutes of daylight.
Hours of Daylight and Twilight in October
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 Arroyo Seco is 7:39 AM on October 27 and the earliest sunrise is 1 hour, 0 minutes earlier at 6:40 AM on October 28.
The latest sunset is 7:26 PM on October 1 and the earliest sunset is 1 hour, 23 minutes earlier at 6:02 PM on October 31.
Daylight saving time (DST) ends at 1:00 AM on October 28, 2018, shifting sunrise and sunset to be an hour earlier.
For reference, on June 21, the longest day of the year, the Sun rises at 6:57 AM and sets 13 hours, 27 minutes later, at 8:24 PM, while on December 21, the shortest day of the year, it rises at 7:12 AM and sets 10 hours, 49 minutes later, at 6:01 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in October
The solar day over the course of October. 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. The transitions to and from daylight saving time are indicated by the 'DST' labels.
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 Arroyo Seco is rapidly decreasing during October, falling from 24% to 8% over the course of the month.
For reference, on September 5, the muggiest day of the year, there are muggy conditions 33% of the time, while on January 10, the least muggy day of the year, there are muggy conditions 0% of the time.
The percentage of time spent at various humidity comfort levels, categorized by dew point.
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 Arroyo Seco is gradually decreasing during October, decreasing from 5.8 miles per hour to 5.3 miles per hour over the course of the month.
For reference, on June 27, the windiest day of the year, the daily average wind speed is 7.0 miles per hour, while on December 2, the calmest day of the year, the daily average wind speed is 5.0 miles per hour.
Average Wind Speed in October
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 Arroyo Seco throughout October is predominantly from the east, with a peak proportion of 72% on October 1.
Wind Direction in October
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 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).
Temperatures in Arroyo Seco are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season in October
The percentage of time spent in various temperature bands. 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 Arroyo Seco are rapidly increasing during October, increasing by 547°F, from 5,587°F to 6,134°F, over the course of the month.
Growing Degree Days in October
The average growing degree days accumulated over the course of October, 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 Arroyo Seco is gradually decreasing during October, falling by 0.6 kWh, from 5.8 kWh to 5.2 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in October
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 Arroyo Seco are 21.548 deg latitude, -99.688 deg longitude, and 3,337 ft elevation.
The topography within 2 miles of Arroyo Seco contains very significant variations in elevation, with a maximum elevation change of 1,801 feet and an average elevation above sea level of 3,309 feet. Within 10 miles contains very significant variations in elevation (5,131 feet). Within 50 miles also contains extreme variations in elevation (10,262 feet).
The area within 2 miles of Arroyo Seco is covered by trees (68%) and shrubs (25%), within 10 miles by trees (66%) and shrubs (30%), and within 50 miles by trees (47%) and shrubs (37%).
This report illustrates the typical weather in Arroyo Seco 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Arroyo Seco.
The estimated value at Arroyo Seco is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Arroyo Seco and a given station.
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.
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.