Few places on earth can claim a climate of such great variety and year-round enchantment as that which graces the Sierra. The four sharply defined seasons bring to the high country a continual round of variety and change. There is no sameness, except perhaps in the probability of sunny days, for sunshine is a major ingredient of the Tahoe seasons.
In over 50 years of recorded history of the weather in the Basin, 80 percent of the days have had sunshine. The probability runs from a December/January/February low of 75% sunshine to a June/July/August high of over 93%. Any given year will provide approximately 240 cloudless days and another 75 days when both sunshine and clouds are recorded. The remaining 50 days are the ones that provide the famous Sierra snowpack...and a wee bit of rain.
Sierra snow is unique. It falls in great quantities in relatively short periods from late November to early April, on a ratio of one day of snowfall for every four days of sunshine. The average winter snowpack is 225 inches, or nearly 20 feet, approximately four times the average in Fairbanks, Alaska. Even the crystalline structure of Sierra Snow is rare. It is said to be unusually reflective and capable of withstanding high winter air temperatures to retain its fluffy perfection on the ski slopes. This reflective quality, coupled with the clarity of the Sierra air can be very dangerous to unwary skiers and sunbathers since the sun's intensity is nearly four times that of the brightest day at sea level.
Average daily high temperatures in December, January and February are 40, 37, and 39 degrees respectively. However, according to meteorologists, these figure are somewhat misleading as they are taken in the shade, when in fact, direct sunlight readings often approach 100 degrees on western exposed snow fields. Therefore, it is not unusual to see spring skiers schussing in cutoff Levi's and tee-shirts, acquiring fantastic tans.
The summer season, like the Tahoe winter, is quite extraordinary. Though easily as dry and sunny as anywhere in the arid desert Southwest, daytime highs rarely exceed 80 degrees. Because of the abundance of heavy pine forests and the moderating influence of the 193 square miles of Lake surface, the evenings do not turn cold. June, July and August average just one day of precipitation each and that can be as little as .10 of an inch. Picnic planning is not a problem in the Tahoe Basin at any time, but in the summer, sun probability is about 93% for the entire 90-day period. Spring and fall temperatures are very similar, as are both seasons' rainfall figures, though the March/April/May period averages somewhat cooler temperatures and more precipitation than the fall. Rainfall is usually recorded 14 days out of Spring's 90-day period and on 13 days in Autumn. Spring's average high daytime temperature is 56 degrees, with May's record high 88 degrees and record low 12 degrees. In the fall, the daytime high average is 57 degrees, with September's record high 87 degrees and low 12 degrees.
Perhaps the most significant feature of the Sierra climate is its ability to change moods in a flash. June, July and August have all recorded temperatures below freezing, while December, January and February have recorded highs in the 60's. The wild winter of 1906-07 brought a total of 884 inches of snowfall, nearly 74 feet! The capricious month of April has seen, over the years, a record temperature spread of 73 degrees, with a record high of 74 degrees and the low a mere one-degree reading.
The surface temperature of the main body of the lake, in the summer, is about 67 degrees. Out in the shallow beaches, it is warmer, varying with the temperature of the air, and swimming is enjoyed by thousands. |