Average Weather in Arroyo Grande California, United States
In Arroyo Grande, the summers are warm, arid, and clear and the winters are cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 42°F to 76°F and is rarely below 34°F or above 88°F.
Based on the tourism score, the best time of year to visit Arroyo Grande for warm-weather activities is from late June to late September.
The warm season lasts for 3.9 months, from June 27 to October 24, with an average daily high temperature above 74°F. The hottest day of the year is September 24, with an average high of 76°F and low of 54°F.
The cool season lasts for 3.5 months, from December 1 to March 19, with an average daily high temperature below 66°F. The coldest day of the year is December 23, with an average low of 42°F and high of 64°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
Hacienda La Calera, Chile (5,683 miles away); Campos do Jordão, Brazil (6,333 miles); and Stutterheim, South Africa (10,612 miles) are the far-away foreign places with temperatures most similar to Arroyo Grande (view comparison).
In Arroyo Grande, 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 Arroyo Grande begins around May 7 and lasts for 5.8 months, ending around October 31. On August 24, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 92% of the time, and overcast or mostly cloudy 8% of the time.
The cloudier part of the year begins around October 31 and lasts for 6.2 months, ending around May 7. On February 17, the cloudiest day of the year, the sky is overcast or mostly cloudy 46% of the time, and clear, mostly clear, or partly cloudy 54% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Arroyo Grande varies throughout the year.
The wetter season lasts 4.5 months, from November 20 to April 3, with a greater than 12% chance of a given day being a wet day. The chance of a wet day peaks at 24% on February 20.
The drier season lasts 7.5 months, from April 3 to November 20. The smallest chance of a wet day is 0% on July 26.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 24% on February 20.
Daily Chance of Precipitation
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. Arroyo Grande experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 6.7 months, from October 12 to May 1, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 18, with an average total accumulation of 3.1 inches.
The rainless period of the year lasts for 5.3 months, from May 1 to October 12. The least rain falls around August 6, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
The length of the day in Arroyo Grande varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 47 minutes of daylight; the longest day is June 21, with 14 hours, 31 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:47 AM on June 12, and the latest sunrise is 1 hour, 38 minutes later at 7:25 AM on November 3. The earliest sunset is at 4:50 PM on December 5, and the latest sunset is 3 hours, 31 minutes later at 8:20 PM on June 28.
Daylight saving time (DST) is observed in Arroyo Grande during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level in Arroyo Grande, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
The average hourly wind speed in Arroyo Grande experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 7.2 months, from November 19 to June 25, with average wind speeds of more than 8.3 miles per hour. The windiest day of the year is April 26, with an average hourly wind speed of 9.5 miles per hour.
The calmer time of year lasts for 4.8 months, from June 25 to November 19. The calmest day of the year is August 24, with an average hourly wind speed of 7.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Arroyo Grande varies throughout the year.
The wind is most often from the west for 5.0 months, from May 2 to October 2, with a peak percentage of 67% on July 30. The wind is most often from the north for 7.0 months, from October 2 to May 2, with a peak percentage of 38% on January 1.
Arroyo Grande 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 3.3 months, from July 30 to November 8, with an average temperature above 59°F. The day of the year with the warmest water is September 26, with an average temperature of 60°F.
The time of year with cooler water lasts for 3.2 months, from March 3 to June 9, with an average temperature below 55°F. The day of the year with the coolest water is April 18, with an average temperature of 54°F.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in Arroyo Grande 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 Arroyo Grande for general outdoor tourist activities is from late June to late September, with a peak score in the first week of August.
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 Arroyo Grande for hot-weather activities is from early July to early October, with a peak score in the second week of September.
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.
While it does not do so every year, freezing temperatures are seen in Arroyo Grande over some winters. The day least likely to be in the growing season is January 4, with a 51% chance.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Arroyo Grande should appear around January 20, only rarely appearing before January 15 or after January 30.
Growing Degree Days
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 3.8 months, from April 30 to August 24, with an average daily incident shortwave energy per square meter above 7.4 kWh. The brightest day of the year is June 22, with an average of 8.5 kWh.
The darker period of the year lasts for 3.3 months, from November 6 to February 14, with an average daily incident shortwave energy per square meter below 3.9 kWh. The darkest day of the year is December 24, with an average of 2.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Arroyo Grande are 35.119 deg latitude, -120.591 deg longitude, and 157 ft elevation.
The topography within 2 miles of Arroyo Grande contains only modest variations in elevation, with a maximum elevation change of 423 feet and an average elevation above sea level of 144 feet. Within 10 miles contains only modest variations in elevation (2,769 feet). Within 50 miles contains large variations in elevation (5,768 feet).
The area within 2 miles of Arroyo Grande is covered by artificial surfaces (61%) and cropland (30%), within 10 miles by grassland (28%) and water (25%), and within 50 miles by water (37%) and grassland (36%).
This report illustrates the typical weather in Arroyo Grande, 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 Grande.
For each station, the records are corrected for the elevation difference between that station and Arroyo Grande 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 Arroyo Grande is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Arroyo Grande and a given station.
Time zones for aiports and weather stations are provided by AskGeo.com .