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When to plant in Clinton, IA

USDA Zone 5b

Here are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Clinton, Iowa — all computed from Clinton's nearest NOAA weather station.

In zone 5b, Clinton gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.

Station · CLINTON #1 · 5.6 km
Last spring frost
April 22
50% chance · 32°F
First fall frost
October 16
50% chance · 32°F
Growing season
177 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for ClintonA year-band showing 32°F frost risk from January to December for Clinton: last spring frost around April 22, first fall frost around October 16, about 177 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

The average first fall frost in Clinton is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →

Frost probability

CLINTON #1 · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Clinton’s own odds, recorded at CLINTON #1.

Frost-probability curves for ClintonProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around April 22 and the first fall frost around October 16, giving about 177 frost-free days.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FMay 17May 2Apr 18Sep 23Oct 6Oct 18
32°FMay 8Apr 22Apr 9Oct 2Oct 16Oct 28
28°FApr 29Apr 13Mar 31Oct 11Oct 25Nov 5

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19
Fall sowopen now
Rutabaga
July 10July 24
Fall sowin 5 days
Broccoli
July 24August 7
Fall sowin 5 days
Cabbage
July 24August 7
Fall sowin 5 days
Carrot
July 24August 7
Fall sowin 5 days
Cauliflower
July 24August 7
Fall sowin 5 days
Napa Cabbage
July 24August 21
Fall sowin 19 days
Beet
August 7August 21
Fall sowin 19 days
Collards
August 7September 4
Fall sowin 19 days
Endive
August 7August 21
Fall sowin 19 days
Escarole
August 7August 21
Fall sowin 19 days
Fennel (Bulb)
August 7August 21
Fall sowin 19 days
Kale
August 7September 4
Fall sowin 19 days
Kohlrabi
August 7September 4
Fall sowin 19 days
Peas
August 7August 21
Fall sowin 19 days
Radicchio
August 7August 21
Fall sowin 19 days
Swiss Chard
August 7August 21
Fall sowin 19 days
Turnip
August 7September 4

Add these crops to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Clinton, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 23 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

CLINTON #1
Primary
6 km · 178 m elevation
SPRING
Apr 22
FALL
Oct 16
FULTON L&D #13
10 km · 180 m elevation
SPRING
Apr 13
FALL
Oct 26
MORRISON
23 km · 193 m elevation
SPRING
Apr 26
FALL
Oct 13

Clinton planting FAQ

When is the last spring frost in Clinton, IA?

Plan for the last spring frost in Clinton around April 22 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.

When is the first fall frost in Clinton, IA?

The first fall frost in Clinton typically arrives around October 16 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.

What hardiness zone is Clinton in?

Clinton is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.

How long is the growing season in Clinton?

Clinton has about 177 frost-free days — a moderate growing season — between the average last spring frost (April 22) and first fall frost (October 16).

When should I plant tomatoes in Clinton?

For Clinton, sow tomatoes indoors about February 25–March 11 and move the seedlings out around April 29, after the last spring frost.

Planting reminders

Never miss a window in Clinton

An email when it’s time to start seeds, transplant, and sow — timed to Clinton’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at CLINTON #1, 6 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Clinton, IA — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00131635. Retrieved from https://blissgarden.com/iowa/clinton.
When to Plant in Clinton, IA — Frost Dates & Zone 5b — BlissGarden