Humidity Levels In San Francisco: What To Expect

The San Francisco bay area is known for its cool, foggy weather. If you’re wondering what the humidity is like in the city, you’ve come to the right place.

If you’re short on time, here’s a quick answer to your question: San Francisco has relatively low humidity levels year-round, averaging between 50-80%. Humidity peaks in winter months.

In this comprehensive guide, we’ll cover everything you need to know about San Francisco’s humidity levels throughout the year. You’ll learn about the factors that influence humidity in the city, seasonal variations, and how San Francisco’s humidity compares to the rest of the country.

What Causes Humidity in San Francisco

San Francisco is known for its unique climate, and one of the factors that contributes to this is its humidity levels. The city experiences a moderate level of humidity throughout the year, which can have an impact on daily life and activities.

There are several factors that contribute to the humidity in San Francisco, including its proximity to the ocean and the famous San Francisco fog.

Proximity to the ocean

One of the main reasons for the humidity in San Francisco is its proximity to the Pacific Ocean. The city is located on the western coast of the United States, with the ocean just a few miles away. As a result, the ocean breeze carries moisture from the water, increasing the humidity levels in the city.

This is especially noticeable in the summer months when the ocean temperatures are warmer.

The ocean not only brings moisture to the air but also affects the temperature in San Francisco. The cool ocean currents can create a stark contrast between the city and the surrounding areas, leading to the formation of the famous fog that rolls in from the coast.

San Francisco fog

The San Francisco fog, also known as “Karl the Fog,” is a natural phenomenon that occurs due to the city’s unique geography. The cool air from the ocean meets the warmer air over the land, causing the moisture in the air to condense and form fog.

This fog can often be seen rolling in from the coast, enveloping the city in a thick blanket.

The fog not only adds to the humidity levels but also has a significant impact on the city’s microclimate. It can affect visibility, temperature, and even daily activities. Locals and visitors alike have come to embrace the fog as a part of San Francisco’s charm and have even given it a name, Karl.

It’s important to note that the humidity levels in San Francisco are generally considered moderate compared to other coastal cities. However, the combination of proximity to the ocean and the presence of the famous fog can create a unique and sometimes damp environment.

To learn more about the weather patterns and humidity in San Francisco, you can visit the National Weather Service website, which provides detailed information and forecasts for the city and its surrounding areas.

Average Humidity Levels in San Francisco

San Francisco is known for its unique climate, influenced by the cool waters of the Pacific Ocean and the surrounding hills. As a result, the city experiences relatively mild and moderate temperatures throughout the year, with humidity levels that can vary depending on the season.


During the winter months in San Francisco, the humidity levels tend to be higher compared to other seasons. This is mainly due to the frequent occurrence of rain and fog in the area. The average humidity during this time hovers around 70%.

It’s important to note that the humidity levels can fluctuate throughout the day, with mornings often being more humid than afternoons. This can create a unique atmosphere in the city, with misty mornings and chilly evenings.


In spring, the humidity levels in San Francisco start to decrease slightly. As the weather begins to warm up, the average humidity drops to around 60%. However, it’s still not uncommon to experience foggy mornings and evenings, especially closer to the coast.

Springtime in San Francisco is often considered one of the best seasons to visit, as the weather becomes more pleasant and the city starts to bloom with colorful flowers.


The summer months in San Francisco bring about the famous phenomenon of “June Gloom,” where the city experiences cooler temperatures and higher humidity levels compared to the surrounding areas. The average humidity during this time can range from 60% to 75%.

Despite the higher humidity, San Francisco’s summer weather is generally quite mild and comfortable, with temperatures rarely exceeding 70 degrees Fahrenheit. The coastal fog often rolls in during the evenings, creating a cozy ambiance in the city.


As fall arrives, the humidity levels in San Francisco begin to decrease once again. The average humidity during this season drops to around 50%, signaling the transition towards cooler and drier weather.

The fall months in San Francisco are known for their beautiful golden hues as the leaves change color, creating a picturesque backdrop for exploring the city.

For more detailed and up-to-date information on humidity levels in San Francisco, you can visit the website.

How Humidity Varies Within the City

San Francisco’s unique geography and topography contribute to the variation in humidity levels across the city. The city’s proximity to the Pacific Ocean plays a significant role in creating different microclimates and humidity patterns throughout the area.

Coastal areas vs inland

Coastal areas in San Francisco tend to experience higher humidity levels compared to inland areas. The cool marine layer that rolls in from the ocean often brings with it increased moisture, resulting in higher humidity near the coast.

Areas such as the Sunset District and Ocean Beach are typically more humid due to their close proximity to the Pacific Ocean.

Inland areas, on the other hand, generally have lower humidity levels. Neighborhoods like the Mission District and the Castro District, which are located further away from the coast, experience drier air and lower humidity.

This is due to the influence of the warmer inland air mass, which has less contact with the ocean and therefore carries less moisture.


San Francisco is known for its microclimates, which are small pockets of weather conditions that differ from the surrounding areas. These microclimates can have a significant impact on humidity levels within the city.

For example, the microclimate in the famous Golden Gate Park tends to be cooler and more humid compared to the rest of the city, as the park is situated in a valley where cool air gets trapped.

Similarly, neighborhoods like Potrero Hill and Bernal Heights often experience higher humidity levels due to their location on elevated terrain. The hills can create a barrier that traps moisture, resulting in increased humidity in these areas.

It’s important to note that while these general patterns exist, humidity levels can vary greatly within different parts of the city on any given day. Factors such as time of year, weather patterns, and even time of day can all influence the humidity you experience in specific locations.

To stay informed about humidity levels in San Francisco, you can refer to local weather forecasts or reliable websites such as the National Weather Service ( By understanding the variations in humidity across the city, you can better prepare for your time in San Francisco and ensure a comfortable experience.

Comparing San Francisco’s Humidity to Other Cities

vs New York City

When it comes to humidity, San Francisco and New York City have significant differences. San Francisco, known for its cool and foggy climate, experiences relatively low humidity levels throughout the year.

On the other hand, New York City, with its hot summers and humid continental climate, tends to have higher humidity levels.

According to The Weather Channel, the average annual relative humidity in San Francisco is around 70%, while in New York City it can reach up to 75%. This means that San Francisco residents can enjoy a more comfortable and less sticky environment compared to their counterparts on the East Coast.

vs Miami

Comparing San Francisco’s humidity to the tropical climate of Miami is like comparing two completely different worlds. While Miami is known for its high humidity levels, San Francisco’s cool coastal climate keeps the humidity relatively low.

In Miami, the average annual relative humidity is around 75-80%, according to the AccuWeather. In contrast, San Francisco’s average annual humidity hovers around 70%, providing residents with a more pleasant and less muggy environment.

So if you’re tired of the humidity and looking for a break, San Francisco might just be the perfect destination for you!

vs Los Angeles

When comparing San Francisco’s humidity to its neighbor to the south, Los Angeles, there are noticeable differences. While both cities are located in California, their climates differ significantly.

Los Angeles has a Mediterranean climate with lower humidity levels compared to San Francisco. According to the National Weather Service, Los Angeles experiences an average annual relative humidity of around 60-65%, while San Francisco’s relative humidity hovers around 70%.

This means that San Francisco tends to have slightly higher humidity levels compared to Los Angeles.

However, it’s important to note that both cities generally have comfortable humidity levels, making them great places to live or visit.

Tips for Dealing With Humidity in San Francisco

Using air conditioning

San Francisco is known for its mild climate, but that doesn’t mean it’s immune to humidity. During the summer months, humidity levels can rise, making it uncomfortable for some people. One effective way to combat the humidity is by using air conditioning.

Whether you have a central air conditioning system or a portable unit, keeping your living space cool and dry can help you feel more comfortable. Make sure to set your thermostat to a comfortable temperature and maintain proper ventilation to keep the air circulating.

Choosing comfortable clothing

When dealing with humidity, it’s important to choose clothing that is breathable and lightweight. Natural fabrics like cotton and linen are great options as they allow air to flow through, preventing sweat from getting trapped against your skin.

Avoid synthetic materials like polyester or nylon, as they tend to trap heat and moisture, making you feel even more uncomfortable. Additionally, consider wearing loose-fitting clothes that allow for better air circulation, helping you stay cool and sweat-free.

Staying hydrated

In humid conditions, our bodies tend to sweat more in order to cool down. This means it’s crucial to stay hydrated throughout the day. Drinking plenty of water helps replenish the fluids lost through perspiration and keeps your body functioning optimally.

Aim to drink at least eight glasses of water each day, and increase your intake if you’re engaging in physical activities or spending time outdoors. Additionally, incorporating hydrating foods like watermelon, cucumbers, and oranges into your diet can also help keep you hydrated.

Remember, staying comfortable in humid weather is all about finding the right balance between cooling yourself down and staying hydrated. By using air conditioning, choosing appropriate clothing, and prioritizing hydration, you can beat the humidity and enjoy all that San Francisco has to offer.


To summarize, while San Francisco experiences higher humidity in the winter, the city maintains relatively comfortable humidity levels year-round compared to many other parts of the country. The ocean and frequent fog help regulate moisture in the air.

We hope this guide gave you a comprehensive overview of what to expect when it comes to humidity in San Francisco. Understanding the city’s average humidity levels and variations can help you plan your wardrobe and activities to stay comfortable.

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