Frost dates for Norman, Oklahoma
In Norman, half of springs have had their last frost by April 3 (and 1 spring in 10 still has one after April 18), and half of falls have had their first frost by November 3, leaving about 212 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
Norman, Oklahoma
Last spring frost
April 3
Half of springs have their last frost by this date. For a safer bet, wait until April 18: only 1 spring in 10 has a frost after that.
First fall frost
November 3
Half of falls have their first frost by this date. In 1 fall in 10 it comes by October 21.
Growing season
212 days
Frost-free days in a typical year. 9 years in 10 get at least 191.
Hardiness zone
7b
2023 USDA map: the coldest night of winter averages 5°F to 10°F. On the 2012 map it was 7a, half a zone colder. All 4 ZIP codes within about 6 miles of the city's center are in zone 7b.
Print a year planner for Norman
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 | March 19 | April 3 | April 18 |
| First frost in fall | October 21 | November 3 | November 17 |
The frost-free season between them runs 212 days in a typical year. In 1 year in 10 it is 234 days or longer, and in 1 year in 10 it is 191 days or shorter.
- Hard freeze (28°F): typically last on March 23 and first on November 12. 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 April 14 and first on October 25. 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 Norman comes between March 19 and April 18, a window of 30 days. That is about average for NOAA's stations (the typical window is 31 days).
Among Oklahoma's 193 NOAA stations with a frost every year, 62 percent have their typical last frost later than Norman does.
Planting calendar for Norman
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.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 16 to February 13 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| January 30 to February 27 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| February | ||
| February 13 to March 6 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| February 20 to March 6 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| February 27 to March 13 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| March | ||
| March 6 to 20 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 6 to 20 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 20 to April 3 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| March 20 to April 3 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| April | ||
| April 3 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| April 17 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| April 17 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| June | ||
| June 8 to 22 | Cabbage for fall Start seeds | set the plants out by July 27 |
| June 28 to July 12 | Broccoli for fall Start seeds | set the plants out by August 16 |
| August | ||
| August 7 | 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 |
| August 11 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 12 | 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 |
| August 16 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| August 17 | 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 |
| August 21 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| August 31 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 10 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| September 20 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 21 | 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 |
| November | ||
| November 19 to 26 | 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 15 days later. That plans around April 18, 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 Norman 3 SSE (station USC00346386), 7 miles from the center of Norman. It sits at about the same elevation, 1,130 feet above sea level. NOAA rates this station's record as representative: at least 10 of the 30 years, with the gaps filled from nearby stations.
Our ZIP code lookup matches these 3 ZIP codes to the same station, so they get the same dates: 73026, 73068, 73093. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Oklahoma City, Oklahoma: last frost around April 4, first frost around November 2 (20 miles away)
- Tulsa, Oklahoma: last frost around March 31, first frost around November 4 (100 miles away)
- Broken Arrow, Oklahoma: last frost around March 30, first frost around November 4 (105 miles away)
See frost dates across Oklahoma, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.