Average Weather in Atwater California, United States
In Atwater, the summers are hot, arid, and clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 38°F to 97°F and is rarely below 29°F or above 104°F.
Based on the tourism score, the best time of year to visit Atwater for warm-weather activities is from early June to late September.
The hot season lasts for 3.6 months, from June 4 to September 24, with an average daily high temperature above 88°F. The hottest day of the year is July 18, with an average high of 97°F and low of 63°F.
The cool season lasts for 2.9 months, from November 23 to February 18, with an average daily high temperature below 62°F. The coldest day of the year is December 30, with an average low of 38°F and high of 54°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
In Atwater, 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 Atwater begins around May 12 and lasts for 5.5 months, ending around October 27. On August 8, 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 27 and lasts for 6.5 months, ending around May 12. On February 6, the cloudiest day of the year, the sky is overcast or mostly cloudy 51% of the time, and clear, mostly clear, or partly cloudy 49% of the time.
Cloud Cover Categories
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Atwater varies throughout the year.
The wetter season lasts 5.2 months, from November 3 to April 10, with a greater than 14% chance of a given day being a wet day. The chance of a wet day peaks at 28% on February 20.
The drier season lasts 6.8 months, from April 10 to November 3. The smallest chance of a wet day is 0% on July 29.
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 28% 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. Atwater experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 7.2 months, from October 6 to May 13, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 15, with an average total accumulation of 2.9 inches.
The rainless period of the year lasts for 4.8 months, from May 13 to October 6. The least rain falls around August 11, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
The length of the day in Atwater varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 35 minutes of daylight; the longest day is June 21, with 14 hours, 44 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:41 AM on June 13, and the latest sunrise is 1 hour, 48 minutes later at 7:29 AM on November 3. The earliest sunset is at 4:44 PM on December 6, and the latest sunset is 3 hours, 43 minutes later at 8:27 PM on June 28.
Daylight saving time (DST) is observed in Atwater 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 Atwater, 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
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed in Atwater experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 4.5 months, from April 10 to August 28, with average wind speeds of more than 7.2 miles per hour. The windiest day of the year is June 6, with an average hourly wind speed of 8.9 miles per hour.
The calmer time of year lasts for 7.4 months, from August 28 to April 10. The calmest day of the year is January 21, with an average hourly wind speed of 5.6 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Atwater varies throughout the year.
The wind is most often from the south for 1.1 weeks, from January 6 to January 14, with a peak percentage of 27% on January 13. The wind is most often from the west for 11 months, from January 14 to December 7, with a peak percentage of 94% on July 21. The wind is most often from the north for 4.3 weeks, from December 7 to January 6, with a peak percentage of 27% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Atwater 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 Atwater for general outdoor tourist activities is from early June to late September, with a peak score in the third 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 Atwater for hot-weather activities is from late June to late August, with a peak score in the third week of July.
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.
The growing season in Atwater typically lasts for 10 months (303 days), from around February 4 to around December 4, rarely starting after March 9, or ending before November 15.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Atwater should appear around February 14, only rarely appearing before February 2 or after February 27.
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 3.5 months, from May 6 to August 24, with an average daily incident shortwave energy per square meter above 7.3 kWh. The brightest day of the year is June 23, with an average of 8.5 kWh.
The darker period of the year lasts for 3.5 months, from November 4 to February 18, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 23, with an average of 2.3 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Atwater are 37.348 deg latitude, -120.609 deg longitude, and 151 ft elevation.
The topography within 2 miles of Atwater is essentially flat, with a maximum elevation change of 52 feet and an average elevation above sea level of 152 feet. Within 10 miles is essentially flat (325 feet). Within 50 miles contains only modest variations in elevation (6,923 feet).
The area within 2 miles of Atwater is covered by cropland (65%) and artificial surfaces (35%), within 10 miles by cropland (78%) and grassland (13%), and within 50 miles by cropland (41%) and grassland (37%).
This report illustrates the typical weather in Atwater, 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 Atwater.
For each station, the records are corrected for the elevation difference between that station and Atwater 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 Atwater is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Atwater and a given station.
The stations contributing to this reconstruction are: Castle Airport (70%, 5.4 kilometers, northeast); Merced Municipal Airport (25%, 11 kilometers, southeast); Modesto City-County Airport (3.2%, 43 kilometers, northwest); and Hollister Municipal Airport (1.1%, 87 kilometers, southwest).
Time zones for aiports and weather stations are provided by AskGeo.com .