SLO County weather is heating up again: Triple-digit temps return to Paso Robles

Much like July this year, August presented contrasting temperature patterns between San Luis Obispo and Santa Barbara counties. In San Luis Obispo County, temperatures were warmer than normal, while in Santa Barbara County, they were average.

At the Paso Robles Airport, the mean temperature for July was 75.2 degrees. The typical mean at the airport is 73.7 degrees. Meanwhile, the San Luis Obispo County Regional Airport recorded a mean of 71.4 degrees, which is 4.2 degrees above normal. Unofficially, this August mean temperature may be the hottest on record in San Luis Obispo, besting the previous record of 71.1 degrees in 1998.

In contrast, Santa Barbara County experienced cooler conditions. The Santa Maria Airport had a mean temperature of 64.6 degrees, compared to its historical average of 64 degrees. The Santa Barbara County Airport reported a mean of 66.7 degrees, about 0.3 degrees warmer than normal.

Historically, August is the warmest month in the inland areas, while September is the warmest month in the coastal valleys and beaches.

An upper-level low-pressure system off the Northern California coastline will continue to produce persistent northwesterly winds and extensive marine low clouds with pockets of mist and drizzle overnight and early in the morning.

Fresh to strong (19 to 31 mph) northwesterly winds will develop along the coastline during the afternoon through Monday. These afternoon winds should be strong enough to mix out the temperature inversion layer, leaving behind sunny skies throughout the Central Coast.

Inland valleys (Paso Robles) temperatures will reach the mid-90s, while the coastal valleys (San Luis Obispo) will range between the high 70s and low 80s. The beaches will warm up to the 60s, except for Cayucos, Avila Beach and Shell Beach, which will reach the high 70s and perhaps even the low 80s through Labor Day.

High pressure will build over California starting Tuesday and will continue through Friday. This condition will create warmer temperatures away from the coastline, with the inland valleys reaching triple-digit levels while the coastal valley will reach the high 80s to low 90s.

Along the coastline, the northwesterly wind will decrease to gentle to moderate (8 to 18 mph) levels, and a stubborn marine layer will continue to hug the coastline, producing mostly overcast skies throughout the day and cooler beach temperatures.

In other words, expect “August Fogust” with large temperature differentials between the beaches and inland valleys.

During the following week, we should see strong to gale-force (25 to 38 mph) northwesterly winds, mostly clear skies and cooler temperatures.

Surf report

A 3- to 5-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 14- second period) is forecast along our coastline through Monday, becoming a 3- to 5-foot northwesterly (290-degree deep-water) swell (with an 8- to 12-second period) on Tuesday through Friday. Increasing northwesterly seas are forecast on Saturday through the following week.

Surface seawater temperatures will range between 56 and 60 degrees through Monday, warming to 57 to 62 degrees on Tuesday through Friday. Seawater temperatures are expected to cool the following week with increasing amounts of upwelling.

On this day in weather history (Sept. 1)

The first day of September has historically experienced record-breaking weather from blazing hot days to recurring lightning and a devastating typhoon.

1955: The temperature in Los Angeles, California, soared to an all-time high of 110 degrees during an eight-day string of 100-degree weather

1979: A home in Centerville, Tennessee, was hit by lightning and destroyed. It marked the third time that the house had been hit by lightning since being built in 1970.

2006: On the other side of the Dateline was Typhoon Ioke, the strongest Central Pacific hurricane in more than decade. Classified as a Category 5 “super typhoon,” it knocked out Wake Island’s weather sensors as it lashed the isle with 155 mph winds with gusts up to 190 mph. Ioke was the first Category 5 typhoon to develop in the central Pacific since record keeping began in the early 1960s.

2017: The high temperature in Paso Robles reached 109 degrees, surpassing the previous record of 107 degrees set in 1998. It was the fifth time in six days a heat record had been set in Paso Robles. A strong temperature inversion layer had once again developed that morning. SLOWeather.com in western San Luis Obispo reported 62 degrees at 6 a.m, while just a short distance away, but at 1,200 feet of altitude, Tim’s place in the Irish Hills reported 88 degrees.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on Twitter @PGE_John.

This story was originally published September 1, 2024 at 5:00 AM.