Climate and Average Weather Year Round in San Joaquin Hills United States

In San Joaquin Hills, the summers are short, warm, arid, and clear and the winters are long, cool, and partly cloudy. Over the course of the year, the temperature typically varies from 48°F to 79°F and is rarely below 42°F or above 86°F.

Based on the tourism score, the best time of year to visit San Joaquin Hills for warm-weather activities is from early June to mid October.

The warm season lasts for 2.9 months, from July 7 to October 2, with an average daily high temperature above 76°F. The hottest month of the year in San Joaquin Hills is August, with an average high of 78°F and low of 64°F.

The cool season lasts for 4.1 months, from November 28 to March 31, with an average daily high temperature below 67°F. The coldest month of the year in San Joaquin Hills is December, with an average low of 49°F and high of 65°F.

In San Joaquin Hills, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in San Joaquin Hills begins around April 23 and lasts for 6.3 months, ending around November 2.

The clearest month of the year in San Joaquin Hills is September, during which on average the sky is clear, mostly clear, or partly cloudy 90% of the time.

The cloudier part of the year begins around November 2 and lasts for 5.7 months, ending around April 23.

The cloudiest month of the year in San Joaquin Hills is February, during which on average the sky is overcast or mostly cloudy 40% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in San Joaquin Hills varies throughout the year.

The wetter season lasts 4.4 months, from November 19 to March 30, with a greater than 10% chance of a given day being a wet day. The month with the most wet days in San Joaquin Hills is February, with an average of 5.4 days with at least 0.04 inches of precipitation.

The drier season lasts 7.6 months, from March 30 to November 19. The month with the fewest wet days in San Joaquin Hills is June, with an average of 0.2 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in San Joaquin Hills is February, with an average of 5.4 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 20% on February 19.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. San Joaquin Hills experiences significant seasonal variation in monthly rainfall.

The rainy period of the year lasts for 6.0 months, from October 22 to April 22, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in San Joaquin Hills is February, with an average rainfall of 2.9 inches.

The rainless period of the year lasts for 6.0 months, from April 22 to October 22. The month with the least rain in San Joaquin Hills is July, with an average rainfall of 0.0 inches.

The length of the day in San Joaquin Hills varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 55 minutes of daylight; the longest day is June 20, with 14 hours, 23 minutes of daylight.

The earliest sunrise is at 5:40 AM on June 11, and the latest sunrise is 1 hour, 31 minutes later at 7:11 AM on November 2. The earliest sunset is at 4:42 PM on December 3, and the latest sunset is 3 hours, 23 minutes later at 8:05 PM on June 28.

Daylight saving time (DST) is observed in San Joaquin Hills during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.

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

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.

San Joaquin Hills experiences some seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.3 months, from June 28 to October 5, during which time the comfort level is muggy, oppressive, or miserable at least 3% of the time. The month with the most muggy days in San Joaquin Hills is August, with 3.9 days that are muggy or worse.

The least muggy day of the year is March 4, when muggy conditions are essentially unheard of.

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 San Joaquin Hills experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.5 months, from November 10 to May 27, with average wind speeds of more than 6.4 miles per hour. The windiest month of the year in San Joaquin Hills is December, with an average hourly wind speed of 7.3 miles per hour.

The calmer time of year lasts for 5.5 months, from May 27 to November 10. The calmest month of the year in San Joaquin Hills is August, with an average hourly wind speed of 5.3 miles per hour.

The predominant average hourly wind direction in San Joaquin Hills varies throughout the year.

The wind is most often from the west for 10 months, from January 25 to November 29, with a peak percentage of 66% on May 21. The wind is most often from the east for 1.9 months, from November 29 to January 25, with a peak percentage of 36% on January 1.

San Joaquin Hills 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 water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.1 months, from July 6 to October 9, with an average temperature above 67°F. The month of the year in San Joaquin Hills with the warmest water is August, with an average temperature of 69°F.

The time of year with cooler water lasts for 4.5 months, from December 8 to April 24, with an average temperature below 61°F. The month of the year in San Joaquin Hills with the coolest water is February, with an average temperature of 59°F.

To characterize how pleasant the weather is in San Joaquin Hills throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit San Joaquin Hills for general outdoor tourist activities is from early June to mid October, with a peak score in the last week of July.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit San Joaquin Hills for hot-weather activities is from mid July to mid September, with a peak score in the last week of August.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

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 San Joaquin Hills 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.

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.

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 experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.9 months, from April 24 to August 20, with an average daily incident shortwave energy per square meter above 7.3 kWh. The brightest month of the year in San Joaquin Hills is June, with an average of 8.3 kWh.

The darker period of the year lasts for 3.2 months, from November 5 to February 11, with an average daily incident shortwave energy per square meter below 4.1 kWh. The darkest month of the year in San Joaquin Hills is December, with an average of 3.1 kWh.

For the purposes of this report, the geographical coordinates of San Joaquin Hills are 33.612 deg latitude, -117.837 deg longitude, and 627 ft elevation.

The topography within 2 miles of San Joaquin Hills contains very significant variations in elevation, with a maximum elevation change of 1,083 feet and an average elevation above sea level of 473 feet. Within 10 miles also contains very significant variations in elevation (1,155 feet). Within 50 miles contains very significant variations in elevation (10,062 feet).

The area within 2 miles of San Joaquin Hills is covered by artificial surfaces (80%), within 10 miles by artificial surfaces (53%) and water (31%), and within 50 miles by water (43%) and shrubs (25%).