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Average Weather in Julian California, United States

In Julian, the summers are warm, arid, and mostly clear and the winters are long, very cold, and partly cloudy. Over the course of the year, the temperature typically varies from 30°F to 85°F and is rarely below 22°F or above 93°F.

Temperature

The hot season lasts for 3.2 months, from June 17 to September 23, with an average daily high temperature above 79°F. The hottest day of the year is August 19, with an average high of 85°F and low of 54°F.

The cold season lasts for 3.9 months, from November 21 to March 16, with an average daily high temperature below 60°F. The coldest day of the year is December 25, with an average low of 30°F and high of 54°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

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

Average Hourly Temperature in JulianJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMcoldcoolwarmvery coldcomfortablefreezing
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In Julian, 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 Julian begins around April 20 and lasts for 6.5 months, ending around November 4. On September 10, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 90% of the time, and overcast or mostly cloudy 10% of the time.

The cloudier part of the year begins around November 4 and lasts for 5.5 months, ending around April 20. On February 20, the cloudiest day of the year, the sky is overcast or mostly cloudy 41% of the time, and clear, mostly clear, or partly cloudy 59% of the time.

Cloud Cover Categories

Cloud Cover Categories in JulianclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Sep 1090%Sep 1090%Feb 2059%Feb 2059%Apr 2075%Apr 2075%Nov 475%Nov 475%clearovercastmostly clearpartly cloudymostly cloudy
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

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

The wetter season lasts 4.8 months, from November 18 to April 11, with a greater than 10% chance of a given day being a wet day. The chance of a wet day peaks at 20% on February 21.

The drier season lasts 7.2 months, from April 11 to November 18. The smallest chance of a wet day is 1% on June 17.

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 17% on February 28.

Daily Chance of Precipitation

Daily Chance of Precipitation in JulianwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 2120%Feb 2120%Jun 171%Jun 171%Jan 116%Jan 116%Nov 1810%Nov 1810%Apr 1110%Apr 1110%rainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

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. Julian experiences significant seasonal variation in monthly rainfall.

The rainy period of the year lasts for 6.1 months, from October 18 to April 23, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 20, with an average total accumulation of 2.4 inches.

The rainless period of the year lasts for 5.9 months, from April 23 to October 18. The least rain falls around June 17, with an average total accumulation of 0.1 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

The sliding 31-day liquid-equivalent quantity of snowfall in Julian does not vary significantly over the course of the year, staying within 0.1 inches of 0.1 inches throughout.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in JulianJanFebMarAprMayJunJulAugSepOctNovDec0.0 in0.5 in1.0 in1.5 in2.0 in2.5 inJan 10.1 inJan 10.1 inJul 310.0 inJul 310.0 inJan 200.1 inJan 200.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Julian varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 58 minutes of daylight; the longest day is June 20, with 14 hours, 20 minutes of daylight.

Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:37 AM on June 11, and the latest sunrise is 1 hour, 30 minutes later at 7:07 AM on November 4. The earliest sunset is at 4:39 PM on December 4, and the latest sunset is 3 hours, 20 minutes later at 7:59 PM on June 29.

Daylight saving time (DST) is observed in Julian 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

Sunrise & Sunset with Twilight and Daylight Saving Time in JulianJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 115:37 AMJun 115:37 AM7:59 PMJun 297:59 PMJun 29Dec 44:39 PMDec 44:39 PM7:07 AMNov 47:07 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

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.

The perceived humidity level in Julian, 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

Humidity Comfort Levels in JulianJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Mar 260%Mar 260%Aug 151%Aug 151%drydrycomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 Julian experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.0 months, from March 16 to July 16, with average wind speeds of more than 7.9 miles per hour. The windiest day of the year is May 23, with an average hourly wind speed of 9.4 miles per hour.

The calmer time of year lasts for 8.0 months, from July 16 to March 16. The calmest day of the year is November 2, with an average hourly wind speed of 6.5 miles per hour.

Average Wind Speed

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Julian varies throughout the year.

The wind is most often from the west for 11 months, from January 12 to December 19, with a peak percentage of 88% on June 8. The wind is most often from the east for 3.4 weeks, from December 19 to January 12, with a peak percentage of 38% on January 1.

Wind Direction

Wind Direction in JulianEWEJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westeastnorthsouth
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

Julian 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 2.9 months, from July 8 to October 5, with an average temperature above 68°F. The day of the year with the warmest water is August 23, with an average temperature of 70°F.

The time of year with cooler water lasts for 4.4 months, from December 8 to April 20, with an average temperature below 61°F. The day of the year with the coolest water is February 6, with an average temperature of 59°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 3.6 months, from April 23 to August 10, with an average daily incident shortwave energy per square meter above 7.5 kWh. The brightest day of the year is June 18, with an average of 8.6 kWh.

The darker period of the year lasts for 3.1 months, from November 6 to February 11, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest day of the year is December 22, with an average of 3.2 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in JulianbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJun 188.6 kWhJun 188.6 kWhDec 223.2 kWhDec 223.2 kWhApr 237.5 kWhApr 237.5 kWhAug 107.5 kWhAug 107.5 kWhNov 64.3 kWhNov 64.3 kWhFeb 114.3 kWhFeb 114.3 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Julian are 33.079 deg latitude, -116.602 deg longitude, and 4,104 ft elevation.

The topography within 2 miles of Julian contains very significant variations in elevation, with a maximum elevation change of 1,903 feet and an average elevation above sea level of 4,145 feet. Within 10 miles contains very significant variations in elevation (5,574 feet). Within 50 miles also contains extreme variations in elevation (10,463 feet).

The area within 2 miles of Julian is covered by shrubs (86%) and grassland (13%), within 10 miles by shrubs (79%) and grassland (16%), and within 50 miles by shrubs (57%).

Data Sources

This report illustrates the typical weather in Julian, 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 Julian.

For each station, the records are corrected for the elevation difference between that station and Julian 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 Julian is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Julian and a given station.

The stations contributing to this reconstruction are: Ramona Airport (30%, 30 kilometers, west); Campo (44%, 52 kilometers, south); Thermal Airport (14%, 74 kilometers, northeast); and El Centro, Naval Air Facility (13%, 91 kilometers, east).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.