Only about half the normal amount of rain fell in San Luis Obispo in January, which usually is one of the biggest months of the year for precipitation.
It is the same situation so far for the 2011-12 rain year that ends in June — slightly more than half the normal rainfall has occurred, according to an analysis by John Lindsey, who has been forecasting local weather for more than 20 years.
Cal Poly, the official home for weather keeping in San Luis Obispo, recorded 2.89 inches of rain in January. That’s 56 percent of the normal total for the month.
That rain came over just four days: Jan. 20 through Jan. 23. Before two storms arrived that weekend, the month was trending to be one of the driest Januarys on record.
From July 1, the start of the rain year, through Tuesday, 7.41 inches of rain were measured at Cal Poly. Normally 12.74 inches would have fallen, Lindsey said. For the year so far, San Luis Obispo has received 59 percent of normal precipitation levels.
“We are in the heart of the rain season right now,” noted Lindsey, a community-relations specialist with PG&E. “With each passing day of dry weather, it makes it more difficult to catch up. But one only has to look at the miracle rains of March 1991 to know there is still a chance.” In that month, more than 13 inches of rain swamped San Luis Obispo after what had been a dry winter.
Lindsey also said that January and February last year were below normal for precipitation. Heavy rains in December 2010 pushed that rain year to an above-normal finish.
The common theme to both years is La Niña, the phenomenon in which sea temperatures are colder than normal along South America.
In a La Niña year, California often gets colder, drier weather. In San Luis Obispo County, the average temperature for December was 2.5 degrees colder than normal thanks to cold nights and cool days, Lindsey said. More abundant daytime highs heated up January, and the mean temperature was normal.
Looking ahead, there is a possibility of a storm next Wednesday, then another at the end of next week, Lindsey said.
But in keeping with the way winter is going this year, the storms “are looking so weak, if we do get rain, it will be very light amounts,” he said. “They don’t look like significant rainmakers at all.”