Average Weather in Blackhawk California, United States
In Blackhawk, the summers are long, warm, arid, and mostly 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 84°F and is rarely below 29°F or above 95°F.
The warm season lasts for 3.9 months, from June 9 to October 7, with an average daily high temperature above 77°F. The hottest day of the year is July 28, with an average high of 84°F and low of 56°F.
The cool season lasts for 2.8 months, from November 25 to February 19, with an average daily high temperature below 59°F. The coldest day of the year is December 31, with an average low of 38°F and high of 53°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 Blackhawk, 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 Blackhawk begins around May 16 and lasts for 5.3 months, ending around October 26. On July 20, 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 26 and lasts for 6.7 months, ending around May 16. On January 11, the cloudiest day of the year, the sky is overcast or mostly cloudy 57% of the time, and clear, mostly clear, or partly cloudy 43% 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 Blackhawk varies throughout the year.
The wetter season lasts 5.2 months, from November 5 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 29% on February 20.
The drier season lasts 6.8 months, from April 10 to November 5. The smallest chance of a wet day is 0% on July 19.
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. Blackhawk experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 7.2 months, from October 5 to May 11, 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 3.4 inches.
The rainless period of the year lasts for 4.8 months, from May 11 to October 5. The least rain falls around July 31, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
The length of the day in Blackhawk varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 33 minutes of daylight; the longest day is June 21, with 14 hours, 47 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:44 AM on June 13, and the latest sunrise is 1 hour, 52 minutes later at 7:36 AM on November 4. The earliest sunset is at 4:48 PM on December 6, and the latest sunset is 3 hours, 45 minutes later at 8:33 PM on June 28.
Daylight saving time (DST) is observed in Blackhawk during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level in Blackhawk, 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 Blackhawk experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.9 months, from April 15 to September 13, with average wind speeds of more than 4.5 miles per hour. The windiest day of the year is June 22, with an average hourly wind speed of 5.5 miles per hour.
The calmer time of year lasts for 7.1 months, from September 13 to April 15. The calmest day of the year is January 21, with an average hourly wind speed of 3.5 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Blackhawk varies throughout the year.
The wind is most often from the west for 9.3 months, from February 9 to November 18, with a peak percentage of 91% on August 10. The wind is most often from the north for 2.7 months, from November 18 to February 9, with a peak percentage of 39% on January 1.
Blackhawk 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 2.5 months, from August 2 to October 18, with an average temperature above 57°F. The day of the year with the warmest water is September 15, with an average temperature of 58°F.
The time of year with cooler water lasts for 5.9 months, from December 15 to June 13, with an average temperature below 54°F. The day of the year with the coolest water is May 3, with an average temperature of 53°F.
Average Water Temperature
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 3.6 months, from May 7 to August 25, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is June 27, with an average of 8.5 kWh.
The darker period of the year lasts for 3.6 months, from November 3 to February 19, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 26, with an average of 2.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Blackhawk are 37.821 deg latitude, -121.908 deg longitude, and 899 ft elevation.
The topography within 2 miles of Blackhawk contains very significant variations in elevation, with a maximum elevation change of 1,473 feet and an average elevation above sea level of 1,060 feet. Within 10 miles contains very significant variations in elevation (3,704 feet). Within 50 miles also contains extreme variations in elevation (4,324 feet).
The area within 2 miles of Blackhawk is covered by grassland (55%) and shrubs (32%), within 10 miles by grassland (65%) and artificial surfaces (17%), and within 50 miles by cropland (26%) and grassland (21%).
This report illustrates the typical weather in Blackhawk, 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 Blackhawk.
For each station, the records are corrected for the elevation difference between that station and Blackhawk 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 Blackhawk is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Blackhawk and a given station.
The stations contributing to this reconstruction are: Livermore Municipal Airport (50%, 16 kilometers, southeast); Buchanan Field Airport (26%, 23 kilometers, northwest); and Hayward Air Terminal Airport (24%, 26 kilometers, southwest).
Time zones for aiports and weather stations are provided by AskGeo.com .