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May Weather in Herald California, United States

Daily high temperatures increase by 7°F, from 77°F to 84°F, rarely falling below 66°F or exceeding 96°F.

Daily low temperatures increase by 4°F, from 50°F to 55°F, rarely falling below 44°F or exceeding 61°F.

For reference, on July 18, the hottest day of the year, temperatures in Herald typically range from 60°F to 94°F, while on December 30, the coldest day of the year, they range from 39°F to 53°F.

Average High and Low Temperature in May in Herald

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 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 in Herald

Average Hourly Temperature in May in HeraldMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMAprJuncoldcoolcoolcomfortablewarmhotcoldcomfortable
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 average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Valverde de Leganés, Spain (5,687 miles away) and Ma’dabā, Jordan (7,387 miles) are the far-away foreign places with temperatures most similar to Herald (view comparison).

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The month of May in Herald experiences decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 37% to 26%.

The clearest day of the month is May 31, with clear, mostly clear, or partly cloudy conditions 74% of the time.

For reference, on January 13, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on July 28, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.

Cloud Cover Categories in May in Herald

Cloud Cover Categories in May in HeraldMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AprJunMay 163%May 163%May 3174%May 3174%May 1167%May 1167%May 2170%May 2170%clearmostly clearovercastmostly cloudypartly cloudy
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
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 Herald, the chance of a wet day over the course of May is decreasing, starting the month at 10% and ending it at 6%.

For reference, the year's highest daily chance of a wet day is 30% on February 20, and its lowest chance is 0% on July 20.

Probability of Precipitation in May in Herald

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).

Rainfall

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 Herald is gradually decreasing, starting the month at 0.9 inches, when it rarely exceeds 2.1 inches, and ending the month at 0.4 inches, when it rarely exceeds 1.3 inches or falls below -0.0 inches.

Average Monthly Rainfall in May in Herald

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 snowfall.

Over the course of May in Herald, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 50 minutes, implying an average daily increase of 1 minute, 39 seconds, and weekly increase of 11 minutes, 34 seconds.

The shortest day of the month is May 1, with 13 hours, 50 minutes of daylight and the longest day is May 31, with 14 hours, 39 minutes of daylight.

Hours of Daylight and Twilight in May in Herald

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 Herald is 6:07 AM on May 1 and the earliest sunrise is 24 minutes earlier at 5:43 AM on May 31.

The earliest sunset is 7:57 PM on May 1 and the latest sunset is 25 minutes later at 8:22 PM on May 31.

Daylight saving time is observed in Herald during 2024, but it neither starts nor ends during May, so the entire month is in standard time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:41 AM and sets 14 hours, 50 minutes later, at 8:31 PM, while on December 21, the shortest day of the year, it rises at 7:18 AM and sets 9 hours, 30 minutes later, at 4:48 PM.

Sunrise & Sunset with Twilight in May in Herald

The solar day over the course of May. 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 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.

Solar Elevation and Azimuth in May in Herald

Solar Elevation and Azimuth in May in HeraldMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMAprJun001010202020303040405050506060700001010202030303040405050606070
northeastsouthwest
Solar elevation and azimuth over the course of May 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for May 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.

Moon Rise, Set & Phases in May in Herald

Moon Rise, Set & Phases in May in HeraldMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMAprJunApr 811:22 AMApr 811:22 AMApr 234:50 PMApr 234:50 PMMay 78:23 PMMay 78:23 PMMay 236:54 AMMay 236:54 AMJun 65:38 AMJun 65:38 AMJun 216:09 PMJun 216:09 PM6:35 AM6:35 AM7:57 PM7:57 PM7:55 PM7:55 PM6:27 AM6:27 AM5:31 AM5:31 AM8:03 PM8:03 PM7:53 PM7:53 PM5:32 AM5:32 AM5:25 AM5:25 AM9:19 PM9:19 PM8:54 PM8:54 PM5:55 AM5:55 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
May 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
50%2:38 AMESE12:37 PMWSW-7:37 AMS231,852 mi
2
37%3:12 AMESE1:51 PMWSW-8:31 AMS229,556 mi
3
26%3:41 AMESE3:04 PMW-9:21 AMS227,625 mi
4
16%4:08 AME4:17 PMW-10:11 AMS226,265 mi
5
8%4:34 AME5:31 PMW-11:00 AMS225,673 mi
6
3%5:01 AMENE6:47 PMWNW-11:50 AMS225,995 mi
7
0%5:31 AMENE8:03 PMWNW-12:42 PMS227,291 mi
8
1%6:06 AMENE9:19 PMWNW-1:38 PMS229,507 mi
9
4%6:47 AMENE10:32 PMNW-2:36 PMS232,476 mi
10
10%7:37 AMNE11:36 PMNW-3:36 PMS235,935 mi
11
18%8:35 AMNE--4:34 PMS239,572 mi
12
27%-12:30 AMNW9:38 AMNE5:29 PMS243,073 mi
13
36%-1:14 AMWNW10:43 AMENE6:20 PMS246,166 mi
14
46%-1:49 AMWNW11:47 AMENE7:06 PMS248,641 mi
15
50%-2:18 AMWNW12:49 PMENE7:49 PMS250,365 mi
16
66%-2:42 AMWNW1:49 PMENE8:29 PMS251,275 mi
17
74%-3:04 AMW2:47 PME9:08 PMS251,378 mi
18
82%-3:24 AMW3:45 PME9:46 PMS250,739 mi
19
89%-3:44 AMW4:44 PME10:26 PMS249,467 mi
20
95%-4:06 AMWSW5:44 PMESE11:07 PMS247,702 mi
21
98%-4:30 AMWSW6:47 PMESE11:53 PMS245,601 mi
22
99%-4:58 AMWSW7:53 PMESE--
23
100%-5:32 AMWSW9:00 PMSE12:42 AMS243,317 mi
24
99%-6:14 AMSW10:05 PMSE1:37 AMS240,990 mi
25
96%-7:05 AMSW11:04 PMSE2:35 AMS238,734 mi
26
91%-8:06 AMSW11:56 PMSE3:35 AMS236,625 mi
27
84%-9:15 AMWSW-4:36 AMS234,708 mi
28
74%12:38 AMESE10:28 AMWSW-5:33 AMS233,003 mi
29
63%1:14 AMESE11:41 AMWSW-6:27 AMS231,524 mi
30
50%1:44 AMESE12:53 PMWSW-7:18 AMS230,296 mi
31
40%2:11 AME2:04 PMW-8:06 AMS229,372 mi

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 Herald is essentially constant during May, remaining around 0% throughout.

For reference, on July 29, 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 in Herald

Humidity Comfort Levels in May in HeraldMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%AprJunMay 10%May 10%May 310%May 310%May 110%May 110%May 210%May 210%comfortablecomfortabledrydry
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 Herald is gradually increasing during May, increasing from 6.8 miles per hour to 7.3 miles per hour over the course of the month.

For reference, on July 13, the windiest day of the year, the daily average wind speed is 7.6 miles per hour, while on October 20, the calmest day of the year, the daily average wind speed is 5.3 miles per hour.

Average Wind Speed in May in Herald

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 Herald throughout May is predominantly from the west, with a peak proportion of 62% on May 29.

Wind Direction in May in Herald

Wind Direction in May in HeraldMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%AprJunwestsouthnorth
northeastsouthwest
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).

The growing season in Herald typically lasts for 11 months (326 days), from around January 19 to around December 10, rarely starting after February 26, or ending before November 17.

The month of May in Herald is reliably fully within the growing season.

Time Spent in Various Temperature Bands and the Growing Season in May in Herald

Time Spent in Various Temperature Bands and the Growing Season in May in Heraldgrowing seasongrowing seasonMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AprJun100%May 16100%May 16coldcoolcomfortablewarmhotvery coldsweltering
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 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 Herald are increasing during May, increasing by 446°F, from 622°F to 1,067°F, over the course of the month.

Growing Degree Days in May in Herald

Growing Degree Days in May in HeraldMay1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131500°F500°F600°F600°F700°F700°F800°F800°F900°F900°F1,000°F1,000°F1,100°F1,100°F1,200°F1,200°F1,300°F1,300°FAprJunMay 1622°FMay 1622°FMay 311,067°FMay 311,067°FMay 11755°FMay 11755°FMay 21904°FMay 21904°F
The average growing degree days accumulated over the course of May, 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 Herald is increasing during May, rising by 1.0 kWh, from 6.9 kWh to 7.9 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in May in Herald

Average Daily Incident Shortwave Solar Energy in May in HeraldMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhAprJunMay 16.9 kWhMay 16.9 kWhMay 317.9 kWhMay 317.9 kWhMay 117.3 kWhMay 117.3 kWhMay 217.6 kWhMay 217.6 kWh
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 Herald are 38.296 deg latitude, -121.244 deg longitude, and 69 ft elevation.

The topography within 2 miles of Herald is essentially flat, with a maximum elevation change of 46 feet and an average elevation above sea level of 68 feet. Within 10 miles is essentially flat (295 feet). Within 50 miles contains only modest variations in elevation (6,020 feet).

The area within 2 miles of Herald is covered by cropland (77%) and grassland (23%), within 10 miles by cropland (63%) and grassland (33%), and within 50 miles by cropland (35%) and grassland (31%).

This report illustrates the typical weather in Herald, 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 Herald.

For each station, the records are corrected for the elevation difference between that station and Herald 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 Herald is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Herald 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 Herald 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 Data

All 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.

Disclaimer

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.

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