Bonny Doon Rainfall Gauge

Highlights of the Current Season - July 1, 2003 - June 30, 2004

          November remained wet, cool to cold, but only one frost. We had a nice break mid-month, and sunny but cool skies prevailed. December started out wet, with one storm after another moving through. High winds and cold rain arrived on December 9th, and continued until the 14th, when a break in the wet pattern emerged. The rainy pattern resumed quickly, and the 21st brought over 3 inches in less than 12 hours. Another big storm brought high winds, heavy rain and cold temperatures on the 24th. The end of the year brought a very powerful storm on the 29th, with over 6 inches of rain and high winds, followed by New Years Day and another 4.5 inches with even higher wind gusts (50+ mph). Temperatures barely reached the upper 30's the first week of the year. The wet pattern ended on January 10th, followed by dry but cool conditions. That pattern broke on January 24th with over 1/2 inch of rain, and highs in the 40's. February began with wet and cold conditions. Two very significant storms in mid-February brought over ten inches of cold rain in just a few days.

          March came in like a lamb, with sunny skies and warm temperatures. Record warm temperatures were the rule until the 20th, when dense fog returned to the coast and high thin clouds marked the end of uncommonly warm conditions. The first rain of March finally arrived on the 25th. But it came and went, and early April was mild and mostly sunny. A cold snap mid-month sent temperatures into the 30's, with passing showers that only left a trace of rainfall. A real rainstorm came ashore on the 19th, soaking the ground and making it feel like winter again. By the afternoon of the 20th, it was clearing and seasonable again. May was seasonable but cooler than normal. High temperatures were only in the upper 40's during the week of the 17th through the weekend of the 23rd. Late light rain fell during the early morning of May 28th, followed by warm and sunny skies. June 17th brought light rain and drizzle and cool temperatures to the mountain. And the summer returned on June 20th with moderate temperatures and sunny skies.

          I keep these unofficial readings as a personal interest. I have seen our reading exceed other gauges that are located at lower elevations nearby, so I figured this might be of interest to others. For rainfall amounts up to 5 inches, I use a retail rain gauge. When amounts overnight are higher than 5 inches, I use, as a backup, a simple vertical wall bucket capable of holding up to 14 inches. I have to use the bucket at least a few times every winter. In years past, I was distrustful about the unusually high rainfall readings, changing gauges and trying various methods and locations to improve accuracy. However, after much experimentation, and then checking with our neighbors, I think we are simply in a micro-climate with more rain than other places. This is the Santa Cruz Mountains, after all. As the Weather Service says, we are in an "Orographically Favored Location." I think that means we get soggy when others simply get wet.

          There is one official California Department of Water Resources weather monitoring site located nearby, at a slightly higher elevation. They match my readings here at 2200' fairly well. You can compare for yourself, at Ben Lomond Mountain (2630', three miles up the road from here). Their measured rainfall tends to be slightly less, but the temperature tracks pretty close to our location.

          As with most places in this region, we are in a "micro-climate". Ours happens to be very wet during the rainy season, due to our location, elevation and southern exposure to incoming storms. During large storms, average winds of 40 to 60 mph are typical here. In December of 1995, we had winds approaching 100 mph, and during February, 1998, peak winds approached 85 mph. The season is officially measured from July 1 to June 30, although rain usually only falls between September and May, a typical "dry and wet" seasonal pattern. Snow does fall here, but it is usually not more than a few inches at a time. The temperature range is not too extreme, and only falls below 25 degrees a few weeks every winter. 1991 was the exception, with lows in the teens for over a week. The winters of 1973, 1975, 1982, 1995, 1998, 2001 and 2002 brought significant snowfall.