The Dayton plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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77° on Nov. 13, 1999, the hottest reading for this week of the year since 1893. Next is 73° in 2001.
Dayton’s center stands about 1,670 ft above sea level. Within three miles the land runs from 1,520 ft to 2,410 ft, a difference of 890 ft: hilly country. The highest named summit within 15 miles is Newby Mountain, about 5,240 ft, 14 miles south-southeast.
Under the town center the state geologic map shows Alluvium (silt, sand), from the Holocene, less than 12,000 years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 6×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Silt. Age: Pleistocene, less than 2.6 million years old. About 19 mi of the line.
Basalt. Age: Late Oligocene to Early Pliocene, 3.6 to 28 million years old. About 4 mi of the line.
Silt, sand. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Dayton reaches the Pacific Ocean by way of the Touchet, the Walla Walla and the Columbia: about 390 river miles.
Lake on the way: Lake Umatilla.
210 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Dayton; river miles along the main stem, rounded.
Dayton has a warm-summer Mediterranean climate. Summer afternoons average 88° in July; winter nights fall to about 26° in January. A normal year brings about 16 inches of snow; with the rain, that comes to about 19 inches of water.
On November 14 Dayton normally reaches 50° and falls to 31°. The record high is 74°, in 1999; the record low −9°, in 1955. The most rain on this date, 1.06 in, fell in 1941.
Normals 1991–2020 and records since 1893 at Dayton 1 WSW, here, 110 ft lower. NOAA, through RCC-ACIS.
