Frost Dates for Corydon, IA

Based on data from Allerton weather station, 5 miles away

Frost Dates

Last Spring Frost (50%) iA 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. April 21
First Fall Frost (50%) iA 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. October 19
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

30% Probability iOnly a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.

Last Spring Frost April 27
First Fall Frost October 13

Hard Freeze (28°F)

Last Spring Hard Freeze April 11
First Fall Hard Freeze October 27
40.76°N, -93.32°W © OpenStreetMap

Growing Season

181 Days April 21 to October 19

USDA Hardiness Zone iHardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.

Zone 5b

Avg. annual minimum: −15 to −10°F (−26 to −23°C)

Learn more

Köppen Climate iThe Köppen climate classification system categorizes climates based on temperature and precipitation patterns.

Dfa Hot-Summer Continental

Hot summers and cold winters with year-round precipitation. Moderate growing season supports warm-season crops like tomatoes, peppers, and corn. Winter protection extends the harvest.

Köppen climate map

Temperature

10° 30° 50° 70° 90°
22°
High: 32°F
Avg: 22°F
Low: 13°F
Jan
27°
High: 37°F
Avg: 27°F
Low: 17°F
Feb
38°
High: 49°F
Avg: 38°F
Low: 28°F
Mar
50°
High: 62°F
Avg: 50°F
Low: 38°F
Apr
61°
High: 71°F
Avg: 61°F
Low: 50°F
May
70°
High: 80°F
Avg: 70°F
Low: 60°F
Jun
75°
High: 85°F
Avg: 75°F
Low: 64°F
Jul
73°
High: 83°F
Avg: 73°F
Low: 62°F
Aug
65°
High: 76°F
Avg: 65°F
Low: 54°F
Sep
52°
High: 64°F
Avg: 52°F
Low: 41°F
Oct
39°
High: 49°F
Avg: 39°F
Low: 28°F
Nov
28°
High: 37°F
Avg: 28°F
Low: 19°F
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 2" 4" 6" 6.3"
2.6"
2.61"
Jan
3.0"
2.97"
Feb
4.5"
4.46"
Mar
5.0"
5.03"
Apr
4.8"
4.80"
May
5.8"
5.82"
Jun
4.9"
4.89"
Jul
5.1"
5.10"
Aug
6.3"
6.27"
Sep
4.5"
4.49"
Oct
3.6"
3.60"
Nov
3.3"
3.28"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec9.5h10.5h11.5h13h14.5h15h14.5h13.5h12.5h11h9.5h9h
Jan: 7:18 AM – 4:42 PM · 9h 23m
Feb: 6:47 AM – 5:13 PM · 10h 26m
Mar: 6:10 AM – 5:50 PM · 11h 41m
Apr: 5:27 AM – 6:33 PM · 13h 06m
May: 4:52 AM – 7:08 PM · 14h 16m
Jun: 4:33 AM – 7:27 PM · 14h 54m
Jul: 4:41 AM – 7:19 PM · 14h 39m
Aug: 5:11 AM – 6:49 PM · 13h 37m
Sep: 5:52 AM – 6:08 PM · 12h 15m
Oct: 6:33 AM – 5:27 PM · 10h 53m
Nov: 7:10 AM – 4:50 PM · 9h 41m
Dec: 7:27 AM – 4:33 PM · 9h 06m
Daylight Longest: 14h 55m · Shortest: 9h 05m

Nearby Stations

Leon 6 Ese, IA April 30 - October 8 Chariton 1 E, IAMay 5 - October 5 Princeton, MO April 25 - October 15 Unionville, MO April 17 - October 22 Centerville, IA April 28 - October 14 Rathbun Dam, IA April 18 - October 23

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