Average Weather in May in Palo Alto Mexico
Daily high temperatures are around 84°F, rarely falling below 77°F or exceeding 90°F. The highest daily average high temperature is 84°F on May 19.
Daily low temperatures increase by 4°F, from 52°F to 56°F, rarely falling below 47°F or exceeding 60°F.
For reference, on May 19, the hottest day of the year, temperatures in Palo Alto typically range from 55°F to 84°F, while on January 8, the coldest day of the year, they range from 39°F to 69°F.
Average High and Low Temperature in May
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on May. 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 May
The month of May in Palo Alto experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 37% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 34% on May 23.
The clearest day of the month is May 23, with clear, mostly clear, or partly cloudy conditions 66% of the time.
For reference, on September 15, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 78%, while on May 23, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 66%.
Cloud Cover Categories in May
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Palo Alto, the chance of a wet day over the course of May is very rapidly increasing, starting the month at 8% and ending it at 22%.
For reference, the year's highest daily chance of a wet day is 43% on July 14, and its lowest chance is 2% on March 23.
Probability of Precipitation in May
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 May in Palo Alto is increasing, starting the month at 0.4 inches, when it rarely exceeds 1.2 inches, and ending the month at 1.4 inches, when it rarely exceeds 3.0 inches or falls below 0.2 inches.
Average Monthly Rainfall in May
Over the course of May in Palo Alto, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 25 minutes, implying an average daily increase of 50 seconds, and weekly increase of 5 minutes, 50 seconds.
The shortest day of the month is May 1, with 12 hours, 58 minutes of daylight and the longest day is May 31, with 13 hours, 23 minutes of daylight.
Hours of Daylight and Twilight in May
The latest sunrise of the month in Palo Alto is 7:16 AM on May 1 and the earliest sunrise is 12 minutes earlier at 7:04 AM on May 31.
The earliest sunset is 8:13 PM on May 1 and the latest sunset is 13 minutes later at 8:27 PM on May 31.
Daylight saving time is observed in Palo Alto during 2018, but it neither starts nor ends during May, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 7:05 AM and sets 13 hours, 28 minutes later, at 8:33 PM, while on December 21, the shortest day of the year, it rises at 7:22 AM and sets 10 hours, 48 minutes later, at 6:09 PM.
Sunrise & Sunset with Twilight in May
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 Palo Alto is essentially constant during May, remaining around 0% throughout.
For reference, on August 6, 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 May
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 Palo Alto is gradually decreasing during May, decreasing from 8.3 miles per hour to 7.7 miles per hour over the course of the month.
For reference, on September 6, the windiest day of the year, the daily average wind speed is 9.4 miles per hour, while on May 27, the calmest day of the year, the daily average wind speed is 7.6 miles per hour.
The lowest daily average wind speed during May is 7.6 miles per hour on May 27.
Average Wind Speed in May
Wind Direction in May
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 Palo Alto typically lasts for 10 months (318 days), from around February 2 to around December 17, rarely starting after March 12, or ending before November 11.
The month of May in Palo Alto is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in May
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 Palo Alto are rapidly increasing during May, increasing by 578°F, from 1,305°F to 1,883°F, over the course of the month.
Growing Degree Days in May
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 Palo Alto is essentially constant during May, remaining within 0.1 kWh of 7.7 kWh throughout.
The highest average daily incident shortwave solar energy during May is 7.8 kWh on May 10.
Average Daily Incident Shortwave Solar Energy in May
For the purposes of this report, the geographical coordinates of Palo Alto are 21.918 deg latitude, -101.965 deg longitude, and 6,650 ft elevation.
The topography within 2 miles of Palo Alto contains only modest variations in elevation, with a maximum elevation change of 417 feet and an average elevation above sea level of 6,658 feet. Within 10 miles contains only modest variations in elevation (1,732 feet). Within 50 miles contains very significant variations in elevation (4,678 feet).
The area within 2 miles of Palo Alto is covered by grassland (93%), within 10 miles by grassland (82%), and within 50 miles by grassland (69%) and shrubs (14%).
This report illustrates the typical weather in Palo Alto 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 Palo Alto.
For each station, the records are corrected for the elevation difference between that station and Palo Alto 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 Palo Alto is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Palo Alto and a given station.
The stations contributing to this reconstruction are: Lic. Jesús Terán Peredo International Airport (58%, 44 kilometers, southwest); Ponciano Arriaga International Airport (15%, 113 kilometers, east); Del Bajío International Airport (15%, 115 kilometers, southeast); and General Leobardo C. Ruiz International Airport (12%, 132 kilometers, northwest).
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.