Climates About San Luis Obispo, CA

San Luis Obispo, often referred to as SLO, is a city on California’s Central Coast. Located about halfway between San Francisco and Los Angeles, SLO has a mild year-round Mediterranean climate characterized by warm, dry summers and cool, wet winters.

In this local’s guide to SLO’s climate, we’ll cover key factors like temperature, precipitation, seasons, microclimates, and weather extremes. Whether you’re considering a move to SLO or just visiting, understanding the area’s climate will help you better plan activities, know what to pack, and determine the best times to visit.

Temperature

SLO enjoys warm to hot summers and mild winters. Here are some key temperature statistics:

Daily Highs/Lows

• Summer Highs: 75°F – 90°F
• Winter Highs: 55°F – 68°F
• Summer Lows: 50°F – 60°F
• Winter Lows: 38°F – 48°F

The warmest months are July and August, while the coldest are December and January. However, temperatures remain relatively comfortable year-round.

Records

• Highest Recorded Temperature: 115°F on June 17, 1961
• Lowest Recorded Temperature: 13°F on January 11, 1949

Average Monthly Temperatures

Here are the normal highs and lows by month:

Month	Average High	Average Low
January	68°F	44°F
February	68°F	45°F
March	69°F	46°F
April	72°F	48°F
May	74°F	51°F
June	77°F	54°F
July	81°F	56°F
August	81°F	56°F
September	79°F	55°F
October	74°F	51°F
November	70°F	47°F
December	65°F	43°F

Precipitation

The region has a Mediterranean climate, with nearly all rain falling between November and March.

Annual Rainfall

SLO receives 15-20 inches of rain per year on average. February is typically the wettest month.

Dry Season

Little to no rain falls from April to October, making these the dry months. Grasses dry out during this time, increasing fire risk.

Wet Season

The wet season runs from November through March, with most rain coming December-February. Steady light rainfall is common.

Extreme Rainfall Events

• Heavy downpours: SLO sometimes gets intense storm systems known as “atmospheric rivers” that bring extreme rainfall over several days. These can cause flooding.
• Dry years: Due to SLO’s Mediterranean climate, rainfall can vary greatly year to year. Droughts are not uncommon.

Average Monthly Rainfall

Here are the normal monthly rainfall totals in inches:

Month	Average Rainfall
January	4.15 inches
February	4.21 inches
March	2.51 inches
April	1.07 inches
May	0.35 inches
June	0.09 inches
July	0.02 inches
August	0.06 inches
September	0.24 inches
October	0.88 inches
November	1.81 inches
December	3.14 inches

Seasons

SLO’s climate is characterized by two main seasons:

Dry Season (April-October)

• Little to no precipitation
• Warm to hot, dry weather
• Low humidity
• Fire danger increases

Wet Season (November-March)

• Majority of annual precipitation
• Cool, damp weather
• Occasional heavy rains and storms
• Mountain snow at higher elevations
• Increased risk of flooding

The transitional months of April and November see a shift between these seasonal patterns.

Microclimates

SLO has several microclimates that see localized weather differences due to topography:

Coastal Areas

• Cooler year-round
• Foggy in early mornings and evenings
• More breezy

Inland Valleys

• Warmer year-round
• Sheltered from ocean breezes and fog

Foothills

• Cooler temps
• Occasional light snow in winter
• More rainfall

Beach Cities

The nearby beach communities of Pismo Beach, Grover Beach, and Avila Beach tend to be 5-10°F cooler than inland SLO in summer due to the ocean’s influence.

Weather Extremes

While SLO generally has pleasant weather year-round, there are some rare weather extremes to be aware of:

Heat Waves

Prolonged periods of excessively hot weather over 90°F sometimes occur in summer, increasing risk of drought and wildfires.

Cold Snaps

Brief cold spells can bring overnight lows down to freezing or even the 20s °F during winter. These are more common in the nearby Santa Lucia Mountains.

Heavy Rain & Storms

Powerful Pacific storm systems can bring heavy rain leading to flooding and landslides, especially between December-March.

Drought

Multi-year droughts are common due to SLO’s Mediterranean climate. Lack of rainfall leads to very dry vegetation and high fire danger.

Wind & Surf

Strong northwesterly winds can develop quickly and create high surf along the coast, causing dangers for boaters, swimmers and beachgoers.

How the Climate Affects Life in SLO

SLO’s mild climate makes for an enjoyable quality of life:

Comfortable Year-Round Temperatures

Residents can stay active outdoors almost any time of year without getting too cold or hot. Winters are especially mild.

Lots of Sunshine

The area averages 260 days of sun per year. Solar power is popular.

Agriculture

The region’s climate supports a bounty of produce like strawberries, avocados, citrus, and wine grapes.

Outdoor Activities

Locals and visitors enjoy hiking, biking, surfing, golf, and more thanks to the mild weather.

Fire Danger

Lack of rain leads to high wildfire risk in summer and fall, when precautions are needed.

Water Supply

Little rainfall means water conservation is important. Droughts can impact reservoirs and crops.

Powerful Storms

Heavy rains between November-March can cause flooding, downed trees, power outages, and debris flows near recent wildfire burn areas.

Tourism

Pleasant weather year round makes SLO a popular weekend getaway and vacation destination. Best times to visit are September-November.

Tips for Visiting SLO Based on Time of Year

Here are some tips on the best times to visit SLO and what to expect weather-wise:

Spring (March – May)

• Mild temperatures perfect for sightseeing
• Green hills and wildflowers bloom
• Less crowded than summer
• Chance of rain till mid-April

Summer (June – August)

• Warm to hot, dry weather
• Busiest tourist season – book ahead
• Sun protection is important
• Ocean temps warmest late August
• Low humidity provides relief from heat

Fall (September – November)

• Warm days and cooler nights
• Less crowded with cheaper lodging
• Prime time for wine country visits
• Rain usually holds off till late November

Winter (December – February)

• Cool, damp weather interspersed with sunny days
• Least crowded time for hotels and dining
• Bring rain jacket and layers
• Some attractions closed or have limited hours

Climate Change Projections for SLO’s Future

Scientists project SLO’s climate will be affected by climate change in the coming decades:

Increasing Temperatures

Average temperatures are expected to rise 3-5°F by 2050. Extreme heat waves over 100°F will become more frequent.

Drier Conditions

Declining rainfall, snowpack, and streamflows will increase drought risk. Drier vegetation raises wildfire danger.

Heavier Rainfall When It Occurs

Global warming will increase the intensity of the biggest rainstorms, worsening flood risk.

Rising Sea Levels

Coastal areas will see more erosion and damage from storms and high tides as sea level slowly encroaches.

Impacts on Agriculture & Ecology

Drier conditions will stress crops and natural ecosystems. Some species may face increasing risk of decline or extinction.

Planning ahead for these changes will help SLO mitigate impacts and maintain quality of life. Careful water management will be key.

Conclusion

From sunny beaches to rolling wine country, SLO’s mild Mediterranean climate makes it a gem of California’s Central Coast and a popular place to live, work, and vacation. While the rains arrive in winter, most days bring plenty of sunshine for enjoying the region’s natural beauty and bounty.

Just be ready for an occasional heavy downpour or heat wave! As climate change affects weather patterns in the decades ahead, SLO will need to adapt to hotter temperatures and greater extremes.