The Slidell 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.
Mostly sunny
Partly cloudy; warmer
Partly cloudy
Mostly sunny
Mostly sunny
Partly cloudy
Mostly sunny
26° on Nov. 12, 2025, the coldest reading for this week of the year since 1956. Next is 27° in 2019.
Slidell’s center stands about 13 ft above sea level. Within three miles the land runs from 0 ft to 40 ft, a difference of 40 ft: nearly flat ground.
Under the town center the state geologic map shows Prairie Terraces (clay, silt, sand), from the Pleistocene, less than 2.6 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Clay. Age: Holocene, less than 12,000 years old. About 7 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 5 mi of the line.
Clay. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
Fine-detrital, coarse-detrital. 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 Slidell reaches Lake Pontchartrain and the Gulf of America by way of the Bayou Bonfouca: about 7 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Slidell; river miles along the main stem, rounded.
Slidell has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 42° in January. About 66 inches of rain fall in a normal year.
On November 14 Slidell normally reaches 70° and falls to 49°. The record high is 82°, in 1989; the record low 29°, in 2019. The most rain on this date, 2.33 in, fell in 1961.
Normals 1991–2020 and records since 1956 at Slidell, here. NOAA, through RCC-ACIS.
