US Grow Zones

South Bend, Indiana: planting zone & frost dates

Last updated · Sources: PRISM/OSU 2023 ZIP zone listings; NOAA NCEI 1991–2020 Climate Normals (station USW00014848); U.S. Census Bureau — see methodology

South Bend is in USDA plant hardiness zone 6a, where the average coldest winter night reaches -10 to -5°F (-23.3 to -20.6°C). The typical last spring frost is around May 7 and the first fall frost around Oct 14.

Hardiness zone6A-10 to -5°F
Last spring frostMay 730% chance of frost after
First fall frostOct 1430% chance of frost before
Growing season170 daysmedian frost-free days

Frost dates

ProbabilityLast spring frost (32°F)First fall frost (32°F)
Safer (10% risk)May 17Oct 5
Typical planning date (30% risk)May 7Oct 14
Median (50%)May 1Oct 19

How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.

Frost data comes from NOAA station SOUTH BEND MICHIANA RGNL AP, IN (USW00014848), 3.2 mi (5.2 km) from the city center and 52 ft higher than the city center (+16 m). Record used for the 1991–2020 normals: 30 years.

Frost probability in spring and fall, South Bend, INChance of a 32°F frost in South Bend, IN, NOAA 1991–2020. Spring: the chance of another frost falls from 90% on Apr 16 to 10% on May 17. Fall: the chance that the first frost has arrived rises from 10% on Oct 5 to 90% on Nov 1.0%50%100%Spring: later frostApr 1Apr 15May 1May 1530%: May 7Fall: frost arrivedOct 1Oct 15Nov 1Nov 1530%: Oct 1432°F frost28°F hard freezeplanning date
Shaded areas show the chance of a 32°F frost: falling through spring, rising through fall. The dashed line is the 28°F hard-freeze curve. Data: NOAA 1991–2020 Normals, station USW00014848.
Frost-free growing season in South Bend, IN1 in 10 risk: May 17 to Oct 5 (141 days); 3 in 10 risk: May 7 to Oct 14 (160 days); Median (50%): May 1 to Oct 19 (171 days); No 28°F freeze: Apr 19 to Oct 31 (195 days). In 9 of 10 years the 32°F-free season is at least 149 days.Frost-free days, spring to fallJFMAMJJASOND1 in 10 risk141 days3 in 10 risk160 daysMedian (50%)171 daysNo 28°F freeze195 days
Frost-free window at three risk levels, plus the window between 28°F hard freezes. Read about what the probabilities mean.

Why your yard may differ from the station: microclimates.

Hardiness zone across South Bend

All 9 ZIP codes covering South Bend are in zone 6a.

ZIP codes in South Bend and their zones
ZIPZoneShare of city land
466286a32.6%
466146a24.3%
466196a11.1%
466156a7.9%
466136a7.7%
466176a6.2%
466016a4.7%
466166a3.4%
466356a1.2%

Vegetable planting calendar for South Bend

Dates are counted from the 30%-risk frost dates above (last frost May 7, first frost Oct 14). Shift a week later in cold spots or low-lying ground.

CropStart indoorsTransplant / plant outDirect sowFall crop sow/plant
TomatoMar 12 – Mar 26May 14 – May 28——
PepperFeb 26 – Mar 12May 21 – Jun 4——
LettuceMar 26 – Apr 9Apr 23 – May 14Apr 9 – May 21Aug 5 – Sep 2
Green Beans——May 14 – Jun 18Jul 22 – Aug 5
Sweet Corn——May 14 – Jun 11—
Zucchini & Summer SquashApr 9 – Apr 16May 14 – May 28May 14 – Jun 4Jul 22 – Aug 5
CucumberApr 9 – Apr 16May 21 – May 28May 14 – Jun 4Jul 22 – Aug 5
Carrot——Apr 16 – May 21Jul 22 – Aug 5
OnionFeb 12 – Feb 26Apr 9 – Apr 23——
Potato—Apr 9 – Apr 30——
BasilMar 26 – Apr 9May 21 – Jun 4May 21 – Jun 11—
Spinach——Mar 26 – Apr 23Aug 19 – Sep 16
KaleMar 12 – Mar 26Apr 9 – Apr 30Apr 9 – Apr 30Aug 5 – Sep 2
BroccoliMar 12 – Mar 26Apr 23 – May 14—Jul 22 – Aug 5
Peas——Mar 26 – Apr 16Aug 5 – Aug 19
EggplantFeb 26 – Mar 12May 21 – Jun 4——
CabbageMar 12 – Mar 26Apr 9 – Apr 23—Jul 22 – Aug 5
Radish——Apr 2 – May 21Sep 2 – Sep 30
Strawberry—Apr 9 – Apr 30——
Beets——Apr 16 – May 28Aug 5 – Aug 19

Nearby cities in Indiana

More: all Indiana cities · other zone 6a cities: Chicago, IL, Denver, CO, Milwaukee, WI, Colorado Springs, CO, Omaha, NE, Aurora, CO, Lincoln, NE, Fort Wayne, IN

South Bend gardening questions

When is the last frost in South Bend, IN?

Plan around May 7. At NOAA's South Bend Michiana Regional Airport, IN station, 3.2 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by May 1, and after May 17 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 19. The 90% and 10% dates are 31 days apart, close to the 36-day median for cities on this site.

When should I plant tomatoes in South Bend, IN?

Start seeds indoors Mar 12 – Mar 26 and set transplants outside May 14 – May 28, once nights stay above 50°F and the soil is near 60°F. That leaves 160 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.

How long is the growing season in South Bend?

About 170 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 149 days, and in 1 year in 10 it runs 189 days or more. In fall there is a 10% chance of frost by Oct 5 and a 30% chance by Oct 14. That is the shortest of the 8 Indiana cities on this site.

When should I plant a fall garden in South Bend?

Count back from the first fall frost (Oct 14): transplant broccoli Jul 22 – Aug 5; sow kale Aug 5 – Sep 2; sow lettuce Aug 5 – Sep 2; sow radishes Sep 2 – Sep 30. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 31. How the math works: succession and fall planting.

Did South Bend's hardiness zone change on the 2023 map?

No. Going by the zone that covers most of the city's land, South Bend is zone 6a on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.

How does South Bend compare with Hammond, IN?

Both are in zone 6a. The typical last spring frost in South Bend (May 7) comes about 7 days later than in Hammond, IN (Apr 30), 63 miles away, and the first fall frost is Oct 14 versus Oct 15. The two cities use different NOAA stations.