Average Weather in Porterville California, United States
In Porterville, the summers are hot, arid, and clear and the winters are cold and partly cloudy. Over the course of the year, the temperature typically varies from 38°F to 97°F and is rarely below 30°F or above 103°F.
Based on the tourism score, the best time of year to visit Porterville for warm-weather activities is from early June to late September.
The hot season lasts for 3.6 months, from June 4 to September 22, with an average daily high temperature above 89°F. The hottest day of the year is July 18, with an average high of 97°F and low of 66°F.
The cool season lasts for 3.1 months, from November 20 to February 25, with an average daily high temperature below 65°F. The coldest day of the year is December 30, with an average low of 38°F and high of 57°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 Porterville, 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 Porterville begins around May 9 and lasts for 5.7 months, ending around November 1. On August 9, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 91% of the time, and overcast or mostly cloudy 9% of the time.
The cloudier part of the year begins around November 1 and lasts for 6.3 months, ending around May 9. On February 21, the cloudiest day of the year, the sky is overcast or mostly cloudy 49% of the time, and clear, mostly clear, or partly cloudy 51% 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 Porterville varies throughout the year.
The wetter season lasts 5.2 months, from November 9 to April 15, with a greater than 12% chance of a given day being a wet day. The chance of a wet day peaks at 23% on February 21.
The drier season lasts 6.8 months, from April 15 to November 9. The smallest chance of a wet day is 0% on August 1.
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 23% on February 21.
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. Porterville experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 6.7 months, from October 15 to May 4, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around January 2, with an average total accumulation of 2.2 inches.
The rainless period of the year lasts for 5.3 months, from May 4 to October 15. The least rain falls around August 3, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
The length of the day in Porterville varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 42 minutes of daylight; the longest day is June 21, with 14 hours, 37 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:38 AM on June 12, and the latest sunrise is 1 hour, 42 minutes later at 7:20 AM on November 3. The earliest sunset is at 4:41 PM on December 5, and the latest sunset is 3 hours, 36 minutes later at 8:17 PM on June 28.
Daylight saving time (DST) is observed in Porterville 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 Porterville, 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, staying within 1% of 1% throughout.
Humidity Comfort Levels
The average hourly wind speed in Porterville experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 3.9 months, from March 27 to July 23, with average wind speeds of more than 5.1 miles per hour. The windiest day of the year is May 31, with an average hourly wind speed of 5.9 miles per hour.
The calmer time of year lasts for 8.1 months, from July 23 to March 27. The calmest day of the year is November 28, with an average hourly wind speed of 4.2 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Porterville varies throughout the year.
The wind is most often from the west for 7.3 months, from March 2 to October 11, with a peak percentage of 60% on July 15. The wind is most often from the east for 4.7 months, from October 11 to March 2, with a peak percentage of 50% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Porterville 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 Porterville 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 Porterville for hot-weather activities is from early July 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 Porterville typically lasts for 9.7 months (293 days), from around February 15 to around December 6, rarely starting after April 4, or ending before November 16.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Porterville should appear around February 9, only rarely appearing before January 28 or after February 21.
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 3.6 months, from May 4 to August 22, with an average daily incident shortwave energy per square meter above 7.5 kWh. The brightest day of the year is June 22, with an average of 8.7 kWh.
The darker period of the year lasts for 3.4 months, from November 5 to February 15, with an average daily incident shortwave energy per square meter below 3.8 kWh. The darkest day of the year is December 22, with an average of 2.6 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Porterville are 36.065 deg latitude, -119.017 deg longitude, and 463 ft elevation.
The topography within 2 miles of Porterville contains only modest variations in elevation, with a maximum elevation change of 318 feet and an average elevation above sea level of 465 feet. Within 10 miles contains only modest variations in elevation (1,936 feet). Within 50 miles contains very significant variations in elevation (13,547 feet).
The area within 2 miles of Porterville is covered by artificial surfaces (62%), cropland (20%), and grassland (12%), within 10 miles by cropland (53%) and grassland (40%), and within 50 miles by cropland (39%) and grassland (23%).
This report illustrates the typical weather in Porterville, 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 Porterville.
For each station, the records are corrected for the elevation difference between that station and Porterville 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 Porterville is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Porterville and a given station.
Time zones for aiports and weather stations are provided by AskGeo.com .