Will it be sunny on Fourth of July? See SLO County holiday weekend forecast
On Sunday, San Luis Obispo County can expect below-seasonal temperatures and low clouds, fog and mist, due to a pattern of gentle to moderate (8 to 18 mph) onshore winds and a persistent marine layer.
From Monday to next Friday, high pressure will strengthen over California from the south, leading to increasing northwesterly winds, a shallower marine layer, more sunshine and a gradual warming trend.
A weak trough of low pressure along the California coastline will continue to maintain a deep marine layer through Sunday, bringing pockets of dense fog and mist during the night and early morning. Skies will gradually clear from the inland and coastal valleys by late morning, with clearing reaching the immediate shoreline during the afternoon.
Temperatures will remain below seasonal averages this weekend.
Inland valleys, including Paso Robles, will see afternoon highs mainly in the low 80s. Coastal valleys, such as San Luis Obispo, will reach the upper 60s to low 70s, while most beaches will remain in the high 50s to low 60s.
The Fourth of July fireworks viewing conditions should be mostly clear away from the ocean. Along the coastline, however, it will be a race against time before the marine layer returns Saturday evening.
Unfortunately, low clouds and fog could threaten fireworks displays in Cayucos and Pismo Beach.
It only takes a slight change in air temperature, the temperature inversion layer’s height and strength, or the direction and speed of the wind to make the difference between a spectacular fireworks show and a colorful glow hidden within the coastal stratus.
The good news is — even if the marine layer moves in before the scheduled 9 p.m. start time Saturday night, the cloud base may remain high enough to provide decent viewing.
Fireworks are designed to burst at a range of altitudes depending on the shell’s size and packing. Most fireworks displays along the Central Coast explode between a few hundred feet and about 1,000 feet above the ground, meaning many of the highest bursts could still be visible below the marine clouds.
Beginning on Monday, high pressure will build northward from the south, compressing the marine layer. As a result, sunshine will become much more widespread, and temperatures will warm across the region, especially away from the immediate coastline.
Meanwhile, the Eastern Pacific High (1,032 millibars) will strengthen and shift eastward toward California, generating fresh to strong (19 to 31 mph) northwesterly winds during the late morning and afternoon. These winds will help scour out the low marine clouds each afternoon, allowing for mostly clear skies along many of the beaches.
Inland valleys, including Paso Robles, will warm into the 90s. Coastal valleys, such as San Luis Obispo, will reach the low to mid-80s, while most beaches will remain in the mid-60s. The exception will be Cayucos, Avila Beach and Shell Beach, where afternoon highs are expected to climb into the high 70s.
Looking ahead, a much warmer weather pattern is expected to develop during the week of July 12 to 18. Inland valleys are forecast to reach triple-digit levels for the first time this year, while coastal areas should also experience a noticeable warming trend as the marine layer becomes shallower and afternoon sunshine becomes more persistent.
If the long-range forecast holds, next week could bring the hottest temperatures of 2026 so far across the inland portions of the Central Coast.
Surf report
A 3- to 4-foot northwesterly (290-degree, deep water) swell (with an 8- to 11-second period) is forecast along the Central Coast on Sunday.
Increasing northwesterly winds along the Central California coastline will generate a 4-to 6-foot northwesterly (300-degree, deep water) sea and swell (with a 5- to 11-second period) on Monday, building to 6 to 8 feet with the same period on Tuesday through next Friday.
A 2- to 3-foot Southern Hemisphere (220-degree, deep water) swell (with a 15- to 18-second period) is forecast along our coastline next Friday.
Seawater temperatures along the immediate coastline will range from 57 to 60 degrees through Sunday before gradually cooling from Monday through next Friday as increasing coastal upwelling brings colder, nutrient-rich water to the ocean surface.
On this date in weather history (July 5)
1900: A spectacular three-day fire began when a bolt of lightning struck a refinery in Bayonne, New Jersey. (David Ludlum)
1916: A hurricane produced 82 mph winds, an 11.6-foot tide and a barometric pressure of 28.92 inches at Mobile, Alabama. (David Ludlum)
1970: The morning low temperature at Death Valley was 103 degrees, and the high that afternoon was 120 degrees. (The Weather Channel)
This week’s temperatures
LOWS AND HIGHS, PASO ROBLES
SUNDAY: 51, 80
MONDAY: 51, 84
TUESDAY: 53, 88
WEDNESDAY: 53, 90
THURSDAY: 55, 92
FRIDAY: 57, 95
SATURDAY: 58, 93
SUNDAY: 61, 90
LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS
SUNDAY: 54, 68
MONDAY: 54, 72
TUESDAY: 53, 74
WEDNESDAY: 54, 77
THURSDAY: 57, 80
FRIDAY: 59, 83
SATURDAY: 59, 82
SUNDAY: 58, 83
John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on X @PGE_John.
