Climate of San Diego
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The climate of
Temperatures
Average monthly temperatures range from 57.3 °F (14.1 °C) in January to 72 °F (22 °C) in August.[citation needed] On average, 344 days a year are hotter than 60 °F (16 °C), but only 25 days are hotter than 80 °F (27 °C).[3]
Late summer and early autumn are typically the hottest times of the year with an average high of 78 °F (26 °C) in August and 77 °F (25 °C) in September.[4] Temperatures occasionally reach 90 °F (32 °C) or higher.[5] Snow and ice are rare in the wintertime, typically occurring only inland from the coast when present.
San Diego experiences marine layer clouds, most often between May and August, which cause cool temperatures, cloudy weather and fog in the morning. Marine layer conditions linger until the heat of the sun becomes strong enough to evaporate the clouds. The local sayings "May gray" and "June gloom" refer to the way in which San Diego has the most trouble shaking off the early morning fog during those months, and cool, cloudy conditions often last into the afternoon or even all day.[6][7]
Temperatures soar to very high readings only on rare occasions, chiefly when easterly winds (known as the "Santa Ana winds") bring hot, dry air from the inland deserts. Although confusing to tourists, newcomers, and out-of-the-region newscasters, this makes October the fire season for San Diego and the rest of Southern California due to low precipitation and sporadic heat waves that the average monthly temperatures do not immediately show. For example, the months with the highest record high temperatures are September at 111 °F (44 °C) and October at 107 °F (42 °C).[4]
The record high temperature at the National Weather Service office in San Diego of 111 °F (44 °C) was on September 26, 1963. The record low temperature was 25 °F (−4 °C) on January 7, 1913.[8] The record high temperature was tied only once and happened on September 27, 2010, 47 years and two days after the set record. Several cities near San Diego, including Los Angeles, broke their all-time records that day.[9]
Precipitation
San Diego on average has 146 sunny days and 117 partly cloudy days a year. The average annual precipitation is less than 12 inches (30 cm), resulting in a borderline
At the National Weather Service office, there are an average of 41 days with measurable precipitation. The wettest year was 1941 with 24.93 inches (63.3 cm) and the driest year was 1953 with 3.23 inches (8.2 cm). The most rainfall in one month was 9.09 inches (23.1 cm) in January 1993. The most rainfall in 24 hours was 3.23 inches (8.2 cm) on April 5, 1926.[10]
Snow
Snow has been recorded falling on lowland San Diego communities only five times in over 125 years of record-keeping.[11] Snow flurries were last seen in San Diego on February 14, 2008 around 1,700 to 1,800 feet (520 to 550 m), and the last measurable snowfall to hit various neighborhoods and suburbs around the city fell on December 13, 1967. In winter, light snow is common in mountainous regions of east and north San Diego County (including Ramona and Julian) above 3,000–4,000 feet (910–1,220 m).[12]
Variation
Climate in the San Diego area often varies dramatically over short geographical distances, due to the city's topography (the Bay, and the numerous hills, mountains, and canyons), thus exhibiting
Compared to national averages
On average, San Diego sees 21 days with some
Data
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Record high °F (°C) | 88 (31) |
91 (33) |
99 (37) |
98 (37) |
98 (37) |
101 (38) |
100 (38) |
98 (37) |
111 (44) |
107 (42) |
100 (38) |
88 (31) |
111 (44) |
Mean maximum °F (°C) | 78.8 (26.0) |
78.6 (25.9) |
80.2 (26.8) |
82.1 (27.8) |
79.3 (26.3) |
79.6 (26.4) |
82.9 (28.3) |
85.2 (29.6) |
90.6 (32.6) |
87.8 (31.0) |
85.4 (29.7) |
77.0 (25.0) |
94.0 (34.4) |
Mean daily maximum °F (°C) | 66.4 (19.1) |
66.2 (19.0) |
67.0 (19.4) |
68.8 (20.4) |
69.5 (20.8) |
71.7 (22.1) |
75.3 (24.1) |
77.3 (25.2) |
77.2 (25.1) |
74.6 (23.7) |
70.7 (21.5) |
66.0 (18.9) |
70.9 (21.6) |
Daily mean °F (°C) | 58.4 (14.7) |
59.0 (15.0) |
60.7 (15.9) |
62.9 (17.2) |
64.8 (18.2) |
67.2 (19.6) |
70.7 (21.5) |
72.4 (22.4) |
71.7 (22.1) |
68.1 (20.1) |
62.7 (17.1) |
57.9 (14.4) |
64.7 (18.2) |
Mean daily minimum °F (°C) | 50.3 (10.2) |
51.8 (11.0) |
54.5 (12.5) |
57.1 (13.9) |
60.0 (15.6) |
62.6 (17.0) |
66.1 (18.9) |
67.5 (19.7) |
66.2 (19.0) |
61.5 (16.4) |
54.8 (12.7) |
49.8 (9.9) |
58.5 (14.7) |
Mean minimum °F (°C) | 43.7 (6.5) |
46.1 (7.8) |
48.7 (9.3) |
51.9 (11.1) |
55.8 (13.2) |
59.3 (15.2) |
63.0 (17.2) |
63.9 (17.7) |
61.8 (16.6) |
55.5 (13.1) |
48.2 (9.0) |
43.0 (6.1) |
42.6 (5.9) |
Record low °F (°C) | 25 (−4) |
34 (1) |
36 (2) |
39 (4) |
45 (7) |
50 (10) |
54 (12) |
54 (12) |
50 (10) |
43 (6) |
36 (2) |
32 (0) |
25 (−4) |
Average precipitation inches (mm) | 1.98 (50) |
2.20 (56) |
1.46 (37) |
0.65 (17) |
0.28 (7.1) |
0.05 (1.3) |
0.08 (2.0) |
0.01 (0.25) |
0.12 (3.0) |
0.50 (13) |
0.79 (20) |
1.67 (42) |
9.79 (249) |
Average precipitation days (≥ 0.01 in) | 6.5 | 7.1 | 6.2 | 3.8 | 2.2 | 0.7 | 0.7 | 0.3 | 0.9 | 2.4 | 3.7 | 5.8 | 40.3 |
Average relative humidity (%)
|
63.1 | 65.7 | 67.3 | 67.0 | 70.6 | 74.0 | 74.6 | 74.1 | 72.7 | 69.4 | 66.3 | 63.7 | 69.0 |
Average dew point °F (°C) | 42.8 (6.0) |
45.3 (7.4) |
47.3 (8.5) |
49.5 (9.7) |
53.1 (11.7) |
57.0 (13.9) |
61.2 (16.2) |
62.4 (16.9) |
60.6 (15.9) |
55.6 (13.1) |
48.6 (9.2) |
43.2 (6.2) |
52.2 (11.2) |
Mean monthly sunshine hours | 239.3 | 227.4 | 261.0 | 276.2 | 250.5 | 242.4 | 304.7 | 295.0 | 253.3 | 243.4 | 230.1 | 231.3 | 3,054.6 |
Percent possible sunshine | 75 | 74 | 70 | 71 | 58 | 57 | 70 | 71 | 68 | 69 | 73 | 74 | 69 |
Source: |
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See or edit raw graph data.
Sea temperatures
Average annual temperature of sea is 65 °F (18 °C), from 59 °F (15 °C) in January to 72 °F (22 °C) in August.[17] Water temperatures have risen since 1950 as measured at Scripps Pier.[18]
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
---|---|---|---|---|---|---|---|---|---|---|---|
59 °F (15 °C) | 61 °F (16 °C) | 61 °F (16 °C) | 62 °F (17 °C) | 64 °F (18 °C) | 67 °F (19 °C) | 70 °F (21 °C) | 72 °F (22 °C) | 70 °F (21 °C) | 68 °F (20 °C) | 65 °F (18 °C) | 62 °F (17 °C) |
Santa Anas
The months of September through April bring warm winds from the desert called "Santa Anas". Occurring about 10 days out of the year, these winds bring sometimes hot, but always dry conditions. Inland, and in mountain passes and canyons, they can burst out in gusts of 100 miles per hour (160 km/h) and can lower relative humidity to single digits, although by the coast they rarely see gusts of over 40 miles per hour (64 km/h). They can spread and worsen wildfires. Because these winds blow from east to west, common perception is that they are pulling hot air from the desert. However, it is not uncommon during a Santa Ana condition for the coast to be even hotter than the desert regions. The Santa Ana winds are actually warm due to barometric pressure increases: As the air is pulled down to sea level from the higher altitudes of the Great Basin and Rocky Mountains to the east, it is compressed and its temperature rises.[19]
Hurricanes
Since the track of most hurricanes is well to the south of San Diego, and the cold
May and June clouds
During the months of May and June, the
Southern Oscillation
San Diego's wet winter season is influenced by the
Ultraviolet index
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
---|---|---|---|---|---|---|---|---|---|---|---|---|
3 | 4 | 6 | 8 | 9 | 10 | 10 | 10 | 8 | 6 | 4 | 3 | 6.7 |
See also
Notes
- ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1991 to 2020.
References
- ^ "National Oceanic and Atmospheric Agency: San Diego climate by month". Wrh.noaa.gov. Retrieved May 4, 2011.
- . Retrieved April 22, 2009.
- ^ "San Diego CA Average Temperatures by Month - Current Results". www.currentresults.com. Retrieved July 9, 2018.
- ^ a b "Intellicast - San Diego Historic Weather Averages in California (92147)". www.intellicast.com. Retrieved July 9, 2018.
- ^ National-Record High Temp: http://www.vroomvroomvroom.com/maximum-temperatures-in-usa/
- ^ Union-Tribune, San Diego. "Less May gray and June gloom, but more rain?". sandiegouniontribune.com. Retrieved July 9, 2018.
- ^ "Marine Layer Information". meteora.ucsd.edu. Retrieved July 9, 2018.
- ^ http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?ca7740; http://www.city-data.com/forum/weather/155963-your-record-high-record-low-10.html
- ^ Enloe, Jesse (December 2, 2012). "CA All-Time Highest Max Temperature Records set on September 27, 2010". NOAA. Retrieved December 2, 2012.
- ^ a b "SAN DIEGO LINDBERGH FLD, CALIFORNIA - Climate Summary".
- ^ "Rowe, P.: "The Day it Snowed on San Diego" San Diego Union-Tribune, December 13, 2007.
- ^ ""Snow play" a popular winter activity at Laguna Mountain Recreation Area, Palomar Mountain and Cuyamaca Rancho State Park (Feb 26 2011)". Archived from the original on May 11, 2011. Retrieved February 27, 2011.
- ^ Conner, Glen. History of weather observations San Diego, California 1849–1948. Climate Database Modernization Program, NOAA's National Climatic Data Center. pp. 7–8.
- ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved June 14, 2021.
- ^ "Summary of Monthly Normals 1991–2020". National Oceanic and Atmospheric Administration. Archived from the original on August 8, 2023. Retrieved June 14, 2021.
- ^ "San Diego/Lindbergh Field CA Climate Normals 1961–1990". National Oceanic and Atmospheric Administration. Archived from the original on August 8, 2023. Retrieved July 18, 2020.
- ^ a b "Pacific Ocean Temperatures on California Coast" - beachcalifornia.com
- ^ a b Lee, Mike (June 18, 2011). "Is global warming changing California Current?". U-T (San Diego Union Tribune). Retrieved June 20, 2011.
- ^ Fovell, Robert, Professor of Atmospheric and Oceanic Sciences, UCLA, "The Santa Ana Winds FAQ http://people.atmos.ucla.edu/fovell/ASother/mm5/SantaAna/santa_ana_faq.html 2016-03-29
- ^ Average UV index San Diego, USA – weather-atlas.com