Bonny Doon Rainfall Gauge

Highlights of the Current Season - July 2002 - June 2003

          Rare light rain fell on August 3rd. This light rain was generated by a heavy marine layer that kept temperatures in the low 50's. And the heat of summer finally arrived in the second week of August. Daytime temperatures were in the 90's, lows in the mid-70's. September was dry and temperate, with highs in the 80's and lows in the 60's and 70's. A cold snap with light rain arrived on Sept. 27th. By the end of the first week of October, warm weather and indian summer returned. The middle of October brought autumn to the mountain, with hazy sunshine, clouds and cool temperatures. Early November began with mild temperatures and clear skies. The first significant rain came ashore on the 7th, bringing nearly 4 inches in 24 hours. This was followed by mild temperatures and dry weather, which lasted until December 6th, when cooler temperatures and light rain returned. An El Nino style major storm came onshore on Dec. 13th, bringing heavy rain and gusty winds. This continuing series of storms brought over 14 inches of rain in less than 2 days, and wind gusts of over 50 mph. Another in a series of storms came ashore on Dec. 19th, bringing snow to the higher elevations. And rain continued into the first day of 2003, making December one of the wettest in recent memory.

          January was very dry and warm spells brought spring-like temperatures to the first few weeks. Rain was lighter than December and did not last long. The dry pattern lingered into February, and broke on the 12th with the first of a series of nice soaking rains. March came in like a lamb, with mild temperatures and sunny skies. Rain returned on the 13th. April started very cold and wet, with temperatures in the low 30's. April 12th brought more wet and cold air flow to the area. Unstable conditions lingered through the end of the month, bringing below average temperatures and rainy skies. May began with moderate rain and cool cloudy conditions. By mid-May, spring appeared to be arriving with warmer temperatures and cool clear nights. The eclipse of the moon on the 15th was clearly visible. Summer arrived during the week of May 19th, when daytime temperatures soared into the 90's, and nights were very warm as well. June was hot, then cold, as June 7th was 85 degrees, and by June 10, it was 45 degrees with light rain. Warmer weather slowly returned by the middle of the month.

          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 to improve accuracy. However, after checking with neighbors, I think we are simply in a micro-climate with more rain than other places.

          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.