Pasadena Climate & Monthly Temperature Overview – United States

Summer (June – August)

Summer in Pasadena is characterized by warm to hot temperatures and low humidity. The average temperature ranges from 75°F (24°C) to 90°F (32°C), with little precipitation. The city experiences minimal rainfall during this time, averaging only 0.1 inches per month. The days are long and sunny, with little cloud cover. The lack of humidity makes the heat relatively bearable, although it can become uncomfortable at times. Outdoor activities and events are popular during this season due to the pleasant weather.

Winter (December – February)

Winters in Pasadena are mild and generally dry. Temperatures average between 45°F (7°C) and 65°F (18°C), with limited rainfall. The city receives an average of 3 inches of rain during the winter months. While temperatures can drop below freezing at night, daytime temperatures typically remain above 50°F (10°C). The weather is often clear and sunny, with occasional cloudy days. The moderate temperatures allow for enjoyable outdoor activities such as hiking, biking, and sightseeing. However, occasional cold spells can bring rain and even some light frost.

Climate Overview in Pasadena, United States

Pasadena, a city in Southern California, United States, experiences a warm Mediterranean climate characterized by dry, warm summers and mild, wet winters. The average temperature throughout the year remains pleasant, with highs rarely exceeding 85°F (29°C) in the warmest months and lows seldom dropping below 45°F (7°C) during the coldest months.

The summer in Pasadena is predominantly dry, with hot and arid conditions. July and August, the hottest months, typically reach an average high of around 85°F (29°C), accompanied by low humidity levels. The heat is often tempered by the cool sea breezes from the nearby Pacific Ocean, providing some relief from the summer’s peak temperatures.

Climate and Cloud Types

Pasadena’s climate is classified as Mediterranean, characterized by warm, dry summers and mild, wet winters. The city experiences an average of 27 inches of rainfall annually, primarily concentrated during the winter months.

Clouds are a common sight in Pasadena, particularly during the winter and spring. The most prevalent cloud type during the winter is the stratus cloud, a low, uniform, gray cloud that often produces drizzle or light rain. During the spring and summer, cumulus clouds, characterized by their puffy, cotton-like appearance, are more common. Cumulus clouds generally indicate fair weather, although they can develop into larger, more ominous clouds that may produce rain or thunderstorms.

Altitude Impact

Pasadena’s altitude also plays a role in the formation of clouds. The city sits at an elevation of approximately 800 feet above sea level, which can influence the formation and dissipation of clouds. Clouds tend to form at higher altitudes, so as air rises and cools, it condenses to form clouds. However, as air descends, it warms and the clouds may evaporate. Pasadena’s altitude means that clouds that form over the surrounding mountains may dissipate as they descend into the city, resulting in fewer cloudy days than in higher-altitude areas.

Annual Precipitation

Pasadena, situated in the southwestern United States, experiences a Mediterranean climate with distinct wet and dry seasons. The city’s annual precipitation averages 325 millimeters (12.8 inches), with the majority falling during the winter months. December and January witness the highest precipitation levels, receiving around 70 millimeters (2.8 inches) per month. Summers, on the other hand, are relatively dry, with July and August receiving less than 5 millimeters (0.2 inches) of rain.

Seasonal Precipitation Variability

Pasadena’s precipitation pattern exhibits a clear seasonal cycle. Wet months typically span from November to April, with steady rainfall and occasional storms bringing a substantial portion of the annual precipitation. During the summer months, from May to October, precipitation becomes scarce due to the prevailing high-pressure system over the region. As a result, the summer months are characterized by warm, sunny conditions with infrequent rainfall.

Annual Rainfall and Distribution

Pasadena, California, experiences a Mediterranean climate with distinct wet and dry seasons. The city’s annual rainfall typically ranges from 16 to 20 inches (41 to 51 centimeters). The majority of rainfall occurs during the winter months, from October to March. During this period, storms from the Pacific Ocean bring frequent showers and occasional heavy downpours. In contrast, the summer months (June to September) are characterized by very little rainfall, with occasional thunderstorms or isolated showers.

Variability and Variability

Pasadena’s rainfall is highly variable on both annual and interannual timescales. The city has experienced years with over 30 inches (76 centimeters) of rainfall and years with less than 10 inches (25 centimeters). This variability is influenced by a combination of factors, including El Niño-Southern Oscillation (ENSO) patterns, atmospheric circulation patterns, and topography. During El Niño years, Pasadena tends to receive more rainfall, while La Niña years are often associated with drier conditions. Additionally, the city’s proximity to the San Gabriel Mountains contributes to orographic lifting, resulting in increased precipitation on the slopes facing the mountains.

History of Snowfall in Pasadena

Snowfall in Pasadena, California, is a rare occurrence. The city has only experienced measurable snowfall on a handful of occasions. The most recent snowfall was in 1949, when 2 inches of snow fell on the morning of January 1st. Prior to that, Pasadena had not seen snowfall since 1882.

The earliest recorded snowfall in Pasadena occurred on January 14, 1882, when 6 inches of snow fell on the city. This was followed by another snowfall on January 16, 1882, when 4 inches of snow fell. These two snowfalls were the heaviest ever recorded in Pasadena.

Causes of Snowfall in Pasadena

Snowfall in Pasadena is caused by a combination of factors, including cold temperatures, moisture, and a lifting mechanism. Cold temperatures are necessary for snow to form, as it prevents the water vapor in the air from evaporating. Moisture is also necessary, as it provides the water vapor that can condense into snow. A lifting mechanism is also necessary, as it forces the moist air upward where it can cool and condense into snow.

In Pasadena, snowfall is most likely to occur during the months of December and January, when temperatures are coldest. The moisture necessary for snowfall can come from the Pacific Ocean, which is located just a few miles west of Pasadena. The lifting mechanism necessary for snowfall can come from the San Gabriel Mountains, which are located just north of Pasadena.

Average Sunshine Hours

Pasadena, California experiences an abundance of sunshine throughout the year, averaging over 280 sunny days annually. During the summer months from June to August, the city basks in an average of 12-13 hours of sunshine each day, with clear and radiant skies dominating the weather pattern. The winter months, from December to February, also offer ample sunshine, with an average of 7-8 hours of daylight. The extended periods of sunshine contribute to Pasadena’s warm and inviting climate and provide ample opportunities for outdoor activities and enjoyment.

UV Index

The intensity of solar radiation in Pasadena varies throughout the year, primarily due to the city’s geographical location and seasonal changes. During the summer months, the UV index is typically in the extreme range, reaching levels of 10 or higher. This indicates a high risk of sunburn and skin damage if exposed to the sun for prolonged periods without proper protection. It is essential to wear sunscreen with a high SPF rating, sunglasses, and protective clothing during these times. In contrast, the UV index during the winter months is significantly lower, falling within the moderate range of 2-5. This reduced exposure allows for more extended outdoor activities without the same level of sun protection concerns.

Moon Visibility in Pasadena, United States

Pasadena, located in Southern California, offers excellent opportunities for moon observation due to its generally clear skies and lack of light pollution compared to larger urban areas. The moon’s visibility varies throughout the month, depending on its phase. During the new moon phase, when the moon is not visible, the night sky is at its darkest, providing optimal conditions for stargazing.

As the moon waxes, it becomes increasingly visible in the night sky. The best time to observe the moon is during its first and third quarters, when half of the moon’s face is illuminated. During these phases, the moon rises around sunset and sets around sunrise, providing ample opportunities for viewing. The full moon, when the entire face of the moon is illuminated, is also a popular time for moon watching, although it can be less visually striking due to the lack of shadows.

Average Humidity Levels in Pasadena

Pasadena experiences a Mediterranean climate, characterized by warm, dry summers and mild, wet winters. The average humidity levels in the city vary throughout the year, but typically remain relatively low. During the summer months (June to September), the average humidity ranges from 45% to 65%, contributing to the warm and dry conditions. The low humidity levels help to mitigate the effects of high temperatures, making it feel less oppressive even during the warmest days.

Seasonal Variations in Humidity

During the winter months (December to February), the average humidity in Pasadena increases slightly, ranging from 55% to 75%. This is due to the increased frequency of precipitation and the cooler temperatures, which allow more moisture to condense in the air. The higher humidity levels during the winter can make the air feel damp and contribute to the formation of fog, especially in the early morning hours. It is important to note that Pasadena’s climate is highly localized, and microclimates can result in significant variations in humidity levels within short distances.

Seasonal Wind Patterns

Pasadena’s wind patterns exhibit distinct seasonal variability. During the winter months (November to April), the city typically experiences prevailing west to northwest winds. These winds are associated with the passage of Pacific storm systems and are often accompanied by rain and cooler temperatures. During the summer months (May to October), the wind regime shifts to predominantly south-to-southwest winds. These winds are part of the California Current Wind System, which brings slightly cooler and moisture-laden air from the Pacific Ocean.

Local Topographic Influences

The Santa Monica Mountains, which lie to the west of Pasadena, play a significant role in shaping the city’s wind patterns. The mountains disrupt the prevailing onshore flow, creating a localized wind pattern known as the “Venturi effect.” As air passes through the narrow canyons in the mountains, it is compressed and accelerated, resulting in stronger winds within Pasadena. This effect is particularly pronounced during the dry months of autumn and winter when cold air flowing from the mountains intensifies the Venturi accelerations.

Ideal Seasons

The best time to visit Pasadena is undoubtedly during the spring (March to May) and fall (September to November) months, when the weather is most pleasant. During this time, the average temperatures range between 60s and 70s Fahrenheit (15s to 21s Celsius). The skies are generally clear, with minimal rainfall and humidity, providing ample opportunities for outdoor exploration and activities. The iconic Rose Parade and Rose Bowl Game are also held in January and January, respectively, making these ideal months for those interested in witnessing these grand events.

Mild Winters and Summers

While the winter months (December to February) can be chilly, Pasadena experiences relatively mild temperatures compared to other parts of the United States. Average temperatures during this time range from the low 40s to low 60s Fahrenheit (6s to 17s Celsius). Although there is a potential for rain, it is infrequent, and sunny days are still common. This makes it an excellent time to visit for those seeking a respite from the cold without sacrificing outdoor enjoyment. Additionally, the summers (June to August) can be warm, with average temperatures reaching into the 80s Fahrenheit (26s to 30s Celsius). However, the low humidity levels make the heat bearable, and the evenings often cool down significantly, providing a comfortable environment for outdoor activities.

Current Solar Energy Landscape in Pasadena

Pasadena, California, boasts significant potential for solar energy utilization due to its abundance of sunshine year-round. The city has embraced solar technology with a high adoption rate, ranking first in solar installations per capita among California cities. As of 2023, Pasadena hosts over 3,500 solar photovoltaic (PV) systems, generating approximately 37 megawatts (MW) of electricity. The city’s comprehensive solar incentive programs have encouraged widespread adoption, with residential and commercial properties alike benefiting from financial incentives, streamlined permitting processes, and technical assistance.

Future Prospects for Solar Energy in Pasadena

Pasadena continues to prioritize the expansion of solar energy within its borders. The city aims to generate 100% of its electricity from renewable sources by 2035, with solar energy playing a central role in achieving this goal. The city’s ambitious “100-Percent Clean Energy by 2035” plan includes measures such as increasing the number of rooftop and ground-mounted solar installations, investing in community solar projects, and promoting solar energy storage systems. Pasadena is also exploring innovative solar technologies, such as solar concentrators and solar thermal systems, to enhance the efficiency and cost-effectiveness of its solar energy production.

Mountain Ranges and Canyons

Pasadena is nestled at the foot of the majestic San Gabriel Mountains, which form a dramatic backdrop to the city. The mountains rise to nearly 10,000 feet, creating a breathtaking panorama that can be seen from many vantage points throughout Pasadena. Within the San Gabriel Mountains lies a network of deep canyons, including Eaton Canyon and the Arroyo Seco, which offer scenic hiking trails and stunning views.

Arroyo Seco and Rose Bowl

The Arroyo Seco, a natural watercourse that originates in the San Gabriel Mountains, flows through the heart of Pasadena. This scenic canyon has been transformed into a vibrant urban greenway, home to the historic Rose Bowl Stadium. The Rose Bowl, nestled within a picturesque setting at the base of the San Rafael Hills, has hosted countless football games, including the annual Rose Bowl Game on New Year’s Day. The stadium’s iconic architecture and beautiful surroundings make it a beloved landmark and a symbol of Pasadena’s rich sporting history.

Bob Hope Airport (BUR)

Bob Hope Airport (BUR), formerly known as Burbank-Glendale-Pasadena Airport, is the closest major airport to Pasadena, California. It is located just 8 miles (13 kilometers) northwest of the city center and offers convenient transportation options for visitors and residents alike. BUR serves a wide range of domestic destinations, including major hubs such as San Francisco, Seattle, Las Vegas, and Phoenix. It also offers limited international flights to Canada and Mexico.

The airport features a modern terminal with amenities such as free Wi-Fi, dining options, and retail stores. There are multiple ground transportation options available, including taxis, ride-sharing services, and public buses. The Metro Orange Line provides direct rail service to downtown Los Angeles and Hollywood. Additionally, BUR offers a convenient shuttle service to Pasadena and other nearby destinations. Travelers appreciate the airport’s proximity to Pasadena, its efficient operations, and its range of transportation options, making it a preferred choice for those visiting the city.

Los Angeles International Airport (LAX)

While Bob Hope Airport is the closest major airport to Pasadena, Los Angeles International Airport (LAX) is another option that offers a wider selection of destinations and international connections. LAX is located approximately 25 miles (40 kilometers) southwest of Pasadena and is accessible via various transportation options. Travelers can take the FlyAway bus service, which offers direct transportation to Union Station in downtown Los Angeles and other destinations in the area. There are also taxi, ride-sharing, and rental car services available at LAX.

LAX is one of the busiest airports in the world, with numerous domestic and international flights. It serves as a major hub for airlines such as American Airlines, Delta Air Lines, United Airlines, and Southwest Airlines. The airport features several terminals, each with its own amenities and facilities. Travelers can expect a wide range of dining, shopping, and entertainment options, as well as services like currency exchange and baggage storage. LAX provides convenient access to Pasadena, although it is farther away than Bob Hope Airport. The choice between the two airports depends on factors such as flight availability, cost, and preferred transportation options.

History and Culture:

Pasadena, situated in the San Gabriel Valley of Southern California, boasts a rich history and vibrant cultural scene. Founded in 1874 as a utopian colony, Pasadena has evolved into a thriving city renowned for its cultural institutions. The renowned Huntington Library, Art Museum, and Botanical Gardens, located in the heart of the city, houses vast collections of art, rare books, and botanical treasures. Additionally, the Pasadena Playhouse, one of the oldest professional theaters in the country, continues to attract renowned actors and performances.

Neighborhoods and Attractions:

Pasadena is divided into distinct neighborhoods, each with its own unique character and attractions. Old Pasadena, the city’s historic downtown, features Victorian architecture, charming shops, and an eclectic array of restaurants. Lake Avenue, known for its lush green spaces and palm tree-lined streets, offers a perfect backdrop for leisurely strolls. The Rose Bowl Stadium, located on the city’s outskirts, has hosted iconic events such as the Rose Bowl Game and countless concerts. Pasadena is also home to the Jet Propulsion Laboratory, a world-renowned center for space exploration, offering guided tours and immersive exhibits that inspire awe and curiosity.