SLO County was well ahead on its rainfall averages. But that’s changing now

The end of January marks the historical midpoint of the rainfall season (July 1–June 30) for San Luis Obispo and Santa Barbara counties, when each location typically receives about half of its annual precipitation.

Overall, the Central Coast remains above average in rainfall, especially across Santa Barbara County. However, a dry stretch in mid-January has trimmed those percentages.

As of Jan. 23, the Santa Barbara Airport has recorded 19.95 inches of rain, roughly 225% of normal, down from 330% at the end of December. The Santa Maria Airport has measured 10.54 inches, or 161% normal at the seasonal halfway point, a decline from 229% around Christmas.

San Luis Obispo County Regional Airport has received 10.45 inches so far, 109% of normal, down from 141% at the end of last month. Paso Robles recorded 8.81 inches of rain, reaching 140% of normal, down from 212% at December’s end.

Rocky Butte, typically the wettest location along the Central Coast, has bucked the broader trend. Instead of declining, totals there have climbed from 113% of normal at the end of December to 122% this month.

The Eastern Pacific High has reestablished itself off the California coast, forcing the storm track well to the north into Northern California, Oregon and Washington, while transient areas of high pressure move across the Great Basin.

This pattern will bring night and morning Santa Lucia (northeasterly) winds along with clear to partly cloudy skies, except for pockets of dense fog and mist in the inland valleys overnight, and widespread tule fog lingering in the Central Valley through Tuesday.

Overnight low temperatures through Monday will drop into the mid- to upper 30s in the inland valleys, including Paso Robles, and into the mid-40s across the coastal valleys such as San Luis Obispo and along the beaches. Daytime highs across the Central Coast will climb into the mid- to high 60s.

A weakening cold front will brush the northern Central Coast on Wednesday, bringing rain as far south as Monterey. Farther south, across San Luis Obispo and Santa Barbara counties, the system will produce increasing northwesterly winds, extensive cloud cover, and cooler temperatures, with highs struggling to reach the lower 60s.

Gusty Santa Lucia winds will redevelop by Thursday and persist during the night and morning into next week, supporting mostly clear skies and a gradual warming trend.

Looking ahead, long-range forecast models continue to indicate predominantly dry conditions through mid-February.

Surf report

A 3- to 5-foot northwesterly (290-degree deep-water) swell (with an 8- to 16-second period) will continue at this level through Sunday, decreasing to 2 to 4 feet (with an 11- to 15-second period) on Monday and will remain at level through Wednesday morning.

Increasing northwesterly winds off the California Coastline will generate a 6- to 8-foot northwesterly (305-degree deep-water) sea and swell with a 7- to 15-second period Wednesday afternoon through next Saturday.

Seawater temperatures will range between 58 and 60 degrees through Wednesday, lowering to 57 to 59 degrees on Thursday and will remain at this level through next Saturday.

On this date in weather history, Jan. 25

1821: The Hudson River froze completely amid the coldest winter recorded in 41 years. Thousands of people made their way across the ice from New York City to New Jersey, where temporary taverns sprang up on the river to offer warmth and refreshments to those passing by. (David Ludlum)

1837: At 7 p.m. a display of the Northern Lights danced above Burlington, Vermont. Its light was equal to the full moon. Snow and nearby objects glowed with a deep red tint. Blue, yellow and white streamers were also noted.

1965: Alta, Utah, was in the midst of a storm that left the town buried under 105 inches of snow establishing a record for the state. (David Ludlum)

1988: High winds created blizzard conditions in the mountains of Colorado. Winds gusted to 109 mph at Echo Lake, and a wind gust to 193 mph was reported atop Mount Evans. (Storm Data)

2021: A cold front passed Diablo Canyon at 10:30 p.m. the night before. The next morning, the northwesterly winds at Diablo Canyon reached 43 mph sustained with gusts to 62 mph. The northwesterly winds increased to 52 mph sustained with gusts 65 mph at 2:45 p.m. that afternoon. Most Central Coast locations recorded between 0.10 and 0.33 of an inch of rain over 12 hours and the snow levels dropped to 2,500 feet.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

SUNDAY: 37, 64

MONDAY: 37, 66

TUESDAY: 36, 67

WEDNESDAY: 41, 60

THURSDAY: 40, 63

FRIDAY: 41, 69

SATURDAY: 40, 67

SUNDAY: 39, 66

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

SUNDAY: 45, 66

MONDAY: 46, 68

TUESDAY: 44, 69

WEDNESDAY: 45, 61

THURSDAY: 48, 66

FRIDAY: 48, 74

SATURDAY: 47, 73

SUNDAY: 48, 72

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