Lower 48 Temperature Isotherms (1991–2020)

Overview

An isarithmic mapping exercise interpolating NOAA 1991–2020 climate normals into smooth temperature surfaces for the contiguous United States, presented as three coordinated panels (annual mean, January, July) at a 5°C isotherm interval in NAD 1983 Contiguous USA Albers. A diverging color scheme is keyed to temperature bands.

Processing

Coordinate Reference Systems

Horizontal

NAD83 Contiguous USA Albers

Methods

• Interpolation of NOAA 1991–2020 station normals to a temperature surface
• Isotherm (isarithmic) contouring at 5°C intervals
• Diverging, banded color scheme keyed to temperature
• Three-panel coordinated layout (mean / January / July)

Deliverables

• Three-panel isotherm map (PDF)

Key Technical Challenge

Producing clean, continuous isotherms from station-based normals while keeping the three panels visually consistent.

Reports & Files