Frost dates for Aberdeen, South Dakota
In Aberdeen, half of springs have had their last frost by May 9 (and 1 spring in 10 still has one after May 22), and half of falls have had their first frost by September 26, leaving about 139 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Aberdeen, South Dakota
Last spring frost
May 9
Half of springs have their last frost by this date. For a safer bet, wait until May 22: only 1 spring in 10 has a frost after that.
First fall frost
September 26
Half of falls have their first frost by this date. In 1 fall in 10 it comes by September 14.
Growing season
139 days
Frost-free days in a typical year. 9 years in 10 get at least 122.
Hardiness zone
4a
2023 USDA map: the coldest night of winter averages −30°F to −25°F. On the 2012 map it was 4b, half a zone warmer. All the ZIP code within about 6 miles of the city's center is in zone 4a.
Print a year planner for Aberdeen
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | April 27 | May 9 | May 22 |
| First frost in fall | September 14 | September 26 | October 7 |
The frost-free season between them runs 139 days in a typical year. In 1 year in 10 it is 157 days or longer, and in 1 year in 10 it is 122 days or shorter.
- Hard freeze (28°F): typically last on April 30 and first on October 4. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on May 19 and first on September 17. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Aberdeen comes between April 27 and May 22, a window of 25 days. That is narrower than at most NOAA stations (the typical window is 31 days), so the typical date is a steadier guide here than in most places.
Among South Dakota's 166 NOAA stations with a frost every year, 40 percent have their typical last frost later than Aberdeen does.
Planting calendar for Aberdeen
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
Your season is too short for a separate fall planting of cabbage and broccoli: sown late enough to be a fall crop, it wouldn't be ready before the typical first frost. Your spring planting is your harvest.
| When | What to do | Why then |
|---|---|---|
| February | ||
| February 21 to March 21 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| March | ||
| March 7 to April 4 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| March 21 to April 11 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| March 28 to April 11 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| April | ||
| April 4 to 18 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| April 11 to 25 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April 11 to 25 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April 25 to May 9 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| April 25 to May 9 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| May | ||
| May 9 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| May 23 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| May 23 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| June | ||
| June 30 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July | ||
| July 4 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| July 5 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July 9 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| July 10 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July 14 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| July 24 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| August | ||
| August 3 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| August 13 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 14 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| October | ||
| October 11 to 18 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
Want more insurance? Shift every spring date 13 days later. That plans around May 22, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Aberdeen (station USW00014929), 3 miles from the center of Aberdeen. It sits at about the same elevation, 1,300 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
Our ZIP code lookup matches these 3 ZIP codes to the same station, so they get the same dates: 57401, 57427, 57479. Hardiness zones are worked out separately for each ZIP code.
The nearest other places with pages
- Fargo, North Dakota: last frost around May 10, first frost around September 30 (125 miles away)
- Bismarck, North Dakota: last frost around May 14, first frost around September 27 (145 miles away)
See frost dates across South Dakota, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.