Planting Date FinderZone, frost date, planting window

Frost dates / Iowa / Cedar Rapids

Frost dates in Cedar Rapids, IA

The station on this page is CEDAR RAPIDS MUNI AP, IA US (USW00014990), 5.9 miles from the city point. Population in the Census 2024 estimate is 137,904.

Zone 5bUSDA average annual extreme minimum -15°F to -10°F, from ZIP 52401 (1.3 miles from the city point used on this page).

Median last 32°F is April 27. Median first 32°F is October 11. The 50% growing-season length is 165 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

ProbabilityDateHow to read it
90%April 13Earlier date. A last 32°F on or after this day is common.
50%April 27Median.
10%May 11Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

ProbabilityDateHow to read it
10%September 25Earlier date. A first 32°F on or before this day is uncommon.
50%October 11Median.
90%October 23Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this longDays
10%184
50%165
90%146

28°F threshold

10%50%90%
Last, on or afterMay 1April 16April 3
First, on or beforeOctober 7October 21November 1
Season at least207 days186 days166 days

36°F threshold

10%50%90%
Last, on or afterMay 20May 6April 23
First, on or beforeSeptember 16October 1October 14
Season at least165 days147 days129 days

Station CEDAR RAPIDS MUNI AP, IA US (USW00014990). Completeness flag S, 30 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 264.6 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Check a crop against this station

Cedar Rapids, IA

Zone 5bAverage annual extreme minimum -15°F to -10°F

Median last 32°F is April 27. Median first 32°F is October 11. The 50% growing-season length is 165 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Iowa. Nearest qualified station: CEDAR RAPIDS MUNI AP, IA US (USW00014990), 5.9 miles. Median last 32°F April 27. Median first 32°F October 11. The 50% growing-season length is 165 days.

Open the ZIP page

32°F probabilities at this station
10%50%90%
Last 32°F on or afterMay 11April 27April 13
First 32°F on or beforeSeptember 25October 11October 23

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

A wall calendar surrounded by vegetables, herbs, seed packets, and watering cans.

Planting calendar

Frost dates for Iowa are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

Date checks use your device’s calendar and appear after the page loads.