June ran hot, then cool in Sisters

Variable temperatures, mostly sunny days, and sparse precipitation characterized the weather in Central Oregon last month. Several exceptionally warm -- make that hot -- afternoons gave local residents a taste of summer.

Maximum temperatures during June averaged 76.2 degrees F., in Sisters. This was 1.1 degree F., higher than the long-term average maximum and, incidentally, was 5.3 degrees F. warmer than June 2001. Elsewhere in Central Oregon, June maximums this year were similar to Sisters with 77.6 degrees F. at Black Butte Ranch, 77.4 degrees F. at Sunriver, and 75.9 degrees F. in Bend.

As is often the case in Central Oregon, temperatures varied throughout the month. Examples for Sisters include maximums of 76 degrees F. (June 4), 59 degrees F. (June 6), 89 degrees F. (June 13), 61 degrees F. (June 17-18), 85 degrees F. (June 20), 95 degrees F. (June 26), and 72 degrees F. (June 28).

Sisters residents experienced 13 days with maximums of 80 degrees F. or higher including readings of 94 degrees F. (June 25), and 95 degrees F. (June 26). Records for the two dates are 98 degrees F. June 25, 1970, and 99 degrees F. June 26, 1987.

Except for Sunriver where June minimums averaged 39.2 degrees F., overnight temperatures were relatively mild with minimums averaging 44.4 degrees F. in Bend, 42.5 degrees F. at Black Butte Ranch, and 41.9 degrees F. in Sisters -- the latter being 2.9 degrees F. higher than the June average minimum and 4.8 degrees F. milder than Sisters average June minimum last year.

Average temperatures are just that. The Sisters weather station noted minimums of 27 degrees F. June 6 and 7, and 28 degrees F. June 8 but also 55 degrees F. on June 27, 28, and 29 -- some of the mildest June minimums on record.

June was the fifth consecutive month with much below-average precipitation in Central Oregon. In the five months February 1 through June 30, precipitation has totaled 2.97 inches at Sunriver, 1.31 inches at the Bend weather station (near Pilot Butte) and 1.27 inches in Sisters. The 30-year average February-June precipitation for Sisters is 4.71 inches.

Between February 1 and June 30, precipitation in Bend has totaled only 1.32 inches, second driest only to the 1.28 inches in the period February 1 through June 30, in 1965. Climatic data for Bend extends back to 1901.

Scientists now forecast that the developing El Niño (ocean warming in the Central Pacific Ocean) may become more extreme than previously forecast. Generally speaking, El Niño events tend to result in fewer winter storms than average, less precipitation, and somewhat milder than average temperatures in the Northwest.