December was seasonably wintry in these parts

December weather in Central Oregon was decidedly winterlike, with chilly days, considerable cloud cover or fog, and periodic snowfalls. Sunshine was a scarce commodity. Weather observers at Black Butte Ranch and Sunriver noted mainly sunny skies on only five dates.

During the shortest "days" of the year, Christmas decorations and lights stood out in sharp contrast to the gray, drab December weather.

With substantial snow having fallen prior to Thanksgiving and periodically renewed during December, there was no need for anyone in the Bend-Sunriver-Sisters area to sing "I'm dreaming of a white Christmas."

One consequence of the cloud cover was that on many days in December there was little difference between maximum and minimum temperatures.

In Sisters, December maximum temperatures ranged between 30 and 39 degrees F. on two-thirds of the days; minimums were in the 20-29 degrees F. range -- also on two-thirds of the days.

Sisters' maximum temperatures averaged 37.7 degrees F., which was 3.3 degrees F. lower than the long-term (1961-90) average of 41.0 degrees F. In fact, 41 degrees F. or higher was reached on only eight days. Sisters' average maximum of 37.7 degrees F. was almost identical to Bend's 37.4 degrees F.

Elsewhere, locally, Black Butte Ranch and Sunriver had December maximum temperatures that averaged 34.8 degrees F. and 37.6 degrees F., respectively.

Normally, Sisters can expect minimum temperatures to drop below 20 degrees F. on one-third of the nights in December, including three in the 0-9 degrees F. range.

This past month, Sisters' extreme minimum temperature was 20 degrees F. (December 28 and 29). This is the first time (period 1961-2001) that Sisters' extreme minimum temperature in December has not dropped below 20 degrees F.

Last year, minimums colder than 20 degrees F. occurred on 18 dates and included three that were below 10 degrees F.

Picking up where November left off, Mother Nature continued to keep the Pacific Northwest supplied with moisture -- mainly in the form of snow in the Cascades and over the Midstate Plateau. Precise measurements of precipitation, when it is in the form of snow, is difficult to obtain, especially if the snow is windblown.

Nonetheless, precipitation totals for Central Oregon weather stations used in this report are as follows: Sisters 2.45 inches including 10.2 inches of snow, Bend 2.33 inches including 8.20 inches of snow, Black Butte Ranch 6.02 inches including 31.0 inches of snow, Sunriver 3.99 inches including 27.8 inches of snow.

There are remarkable differences in precipitation amounts between Black Butte Ranch and Sisters.

This was again evident in December. Except for Sunriver, a little of the precipitation was in the form of rain which shrank the pre-existing snowpack --until the next snowfall arrived.

Inclement weather periodically made driving conditions difficult over the Santiam Pass during December and traffic delays occurred on several occasions.

By the end of December, snowpack and the water content of the snow were much above average in many parts of Oregon.

Raymond R. Hatton is the author of "Sisters Country Weather and Climate," "Oregon's Sisters Country," and other books on the region.