What is the soil temperature in ZIP code 83421 today?

About 42°F on average in the top 4 inches (0–10 cm), low 38°F and high 48°F, from NOAA's GFS model run of Nov 11, 12:00 UTC (7 am Eastern). It is a model value for a grid cell 3.8 km from the ZIP centre, not a reading from your yard.

Is it time for crabgrass preventer in 83421?

The spring window is closed. It opens again when the soil holds 50°F. Last spring the soil held 50°F from Mar 22 and 55°F from Jun 17.

ZIP 83421 · Rexburg, ID · Nov 11, 2026

Soil temperature for ZIP code 83421

42°Faverage today, 0–4 in deep (modelled)
low 38°F · high 48°F

Modelled by NOAA GFS, not measured · run Nov 11, 12:00 UTC (7 am Eastern) · grid cell 3.8 km from the ZIP centre point

On a week ago

1° warmer

42°F on Nov 4

5-day mean

41°F

what the verdicts use

Held 55°F last spring

Jun 17

crabgrass germination temperature

What the soil says today

Pre-emergentSeason over
Cool-season seedToo late in the season
Warm-season seedToo cold
TomatoesToo cold
Peas and lettuceWarm enough

From the 5-day mean of the modelled 0–4 in layer.

Soil temperature, 0–4 in: last 7 days and next 7

°F, modelled. Dots and line: daily average (dashed = forecast); bars: low to high; green band: 50–55°F.

View as table

Day	Average	Low	High
Nov 4	41.6°F	38.8°F	46.1°F	analysis
Nov 5	40.0°F	37.0°F	43.6°F	analysis
Nov 6	39.0°F	35.7°F	43.4°F	analysis
Nov 7	39.3°F	35.5°F	45.2°F	analysis
Nov 8	40.7°F	37.3°F	45.5°F	analysis
Nov 9	41.4°F	38.4°F	45.5°F	analysis
Nov 10	41.3°F	38.2°F	45.7°F	analysis
Today	42.2°F	38.4°F	48.0°F	analysis
Nov 12	43.1°F	39.5°F	48.4°F	forecast
Nov 13	43.4°F	40.4°F	47.5°F	forecast
Nov 14	42.5°F	41.9°F	43.8°F	forecast
Nov 15	39.8°F	36.9°F	43.0°F	forecast
Nov 16	39.1°F	36.2°F	43.6°F	forecast
Nov 17	40.1°F	36.6°F	44.8°F	forecast

Source: NOAA NCEP GFS 0.25°, 0–10 cm soil temperature, run Nov 11, 12:00 UTC (7 am Eastern).

Spring 2026 threshold dates

From the 5-day mean held for 10 days or more.

Soil	What it means	Held from (spring 2026)
40°F	Peas and lettuce	Mar 18
50°F	Pre-emergent window opens	Mar 22
55°F	Crabgrass can germinate	Jun 17
60°F	Tomatoes	not reached
65°F	Warm-season grass seed	not reached

Rexburg, ID, 28 km away: the full city page, with the 2026 season chart, growing degree days and nearby cities →

Nearby ZIP codes

Today's modelled average.

83445 43°F · 83451 44°F · 83436 42°F · 83438 43°F · 83420 41°F · 83448 44°F · 83460 44°F · 83440 44°F

More: crabgrass timing in Idaho · every Idaho city · how accurate the model is.

Questions

What is the soil temperature in ZIP code 83421 today?: About 42°F on average in the top 4 inches (0–10 cm), low 38°F and high 48°F, from NOAA's GFS model run of Nov 11, 12:00 UTC (7 am Eastern). It is a model value for a grid cell 3.8 km from the ZIP centre, not a reading from your yard.
Is it time for crabgrass preventer in 83421?: The spring window is closed. It opens again when the soil holds 50°F. Last spring the soil held 50°F from Mar 22 and 55°F from Jun 17.

Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)); 2025 Gazetteer ZIP Code Tabulation Areas (ZCTA) and 2024 cartographic boundary state outlines (U.S. Census Bureau).