The Portland 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.
Sunny
Mostly sunny; warmer
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Partly cloudy
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12° on Nov. 15, 1969, the coldest reading for this week of the year since 1955. Next is 13° in 2019.
Portland’s center stands about 800 ft above sea level. Within three miles the land runs from 670 ft to 870 ft, a difference of 200 ft: gently rolling country. The highest named summit within 15 miles is Pitt Hill, about 960 ft, 10 miles south.
Under the town center the state geologic map shows St. Louis Limestone and Warsaw Limestone, from the Carboniferous, 324 to 359 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 49×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 11 mi of the line.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 6 mi of the line.
Shale, limestone. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.
Chert. Age: Carboniferous, 324 to 359 million years old. About 2 mi of the line.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 1 mi of the line.
Limestone. Age: Silurian, 422 to 445 million years old. About 1 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 Portland reaches the Gulf of America by way of Summers Branch, the Red River, the Cumberland, the Ohio and the Mississippi: about 1,240 river miles.
Lake on the way: Bards Lake.
970 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Portland; river miles along the main stem, rounded.
Portland has a humid subtropical climate. Summer afternoons average 89° in July; winter nights fall to about 27° in January. About 54 inches of rain fall in a normal year, with about 2 inches of snow.
On November 14 Portland normally reaches 59° and falls to 38°. The record high is 77°, in 1964; the record low 15°, in 2019. The most rain on this date, 1.54 in, fell in 2024.
Normals 1991–2020 and records since 1955 at Portland Sewage Plant, here. NOAA, through RCC-ACIS.
