The Hamilton 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.
Chance of showers
Partly cloudy; warmer
Showers likely
Showers likely; cooler
Mostly cloudy
Chance of showers
Chance of showers
74° on Nov. 12, 1999, the hottest reading for this week of the year since 1911. Next is 69° in 1990.
Hamilton’s center stands about 3,570 ft above sea level. Within three miles the land runs from 3,500 ft to 4,100 ft, a difference of 600 ft: hilly country. The highest named summit within 15 miles is Ward Mountain, about 9,100 ft, 8 miles southwest.
Under the town center the state geologic map shows Gravel, from the Pleistocene to Holocene, less than 1.8 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 4×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granitic. Age: Cretaceous, 66 to 145 million years old. About 8 mi of the line.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 7 mi of the line.
Quartzite, metasiltstone, argillite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Siltstone, sedimentary-breccia, conglomerate. Age: Early Eocene to Early Miocene, 16 to 56 million years old. About 3 mi of the line.
Conglomerate, sandstone, siltstone. Age: Early Miocene to Pliocene, 2.6 to 20 million years old. About 2 mi of the line.
Gravel, sand, silt. Age: Pleistocene to Holocene, less than 1.8 million years old. About 0.9 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 Hamilton reaches the Pacific Ocean by way of the Bitterroot, the Clark Fork, the Pend Oreille and the Columbia: about 1,120 river miles.
Lakes on the way: Lake Pend Oreille, Lake Umatilla and Noxon Rapids Reservoir.
460 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Hamilton; river miles along the main stem, rounded.
Hamilton has a warm-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 19° in January. A normal year brings about 17 inches of snow; with the rain, that comes to about 12 inches of water.
On November 14 Hamilton normally reaches 43° and falls to 25°. The record high is 65°, in 1995; the record low −4°, in 1955. The most rain on this date, 0.42 in, fell in 1941.
Normals 1991–2020 and records since 1911 at Stevensville, 18 miles north, 230 ft lower. NOAA, through RCC-ACIS.
