Centennial, WY frost dates
Last spring frostJun 2median date
First fall frostSep 19median date
Growing season109 daysfrost-free
Hardiness zone5aZone 5a
How Centennial compares
- In 8 years out of 10, the last spring frost in Centennial falls between May 22 and June 20, a 29-day window. The first fall frost falls between September 3 and October 2.
- The median last frost is 12 days later than the Wyoming median of May 21.
- Its 109-day growing season is longer than 20% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 30 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 225 nights a year at or below 32°F.
- Compared with Cheyenne, WY, 103 km away, the last frost here is 21 days later than there and the growing season is 33 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 22 |
| 50% (median) | June 2 |
| 10% (safe for tender plants) | June 20 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 3 |
| 50% (median) | September 19 |
| 90% (late) | October 2 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Centennial, WY
Centennial, WY frost dates — last frost Jun 2, first frost Sep 19, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 10 to Mar 24Transplant outside: May 5 to May 19
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Apr 7 to Apr 21Transplant outside: Jun 9 to Jun 23
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26Sow outdoors: May 5 to Jun 9Plant for fall: Jul 25 to Aug 22
Start indoors: Apr 7 to Apr 21Transplant outside: May 5 to May 19Sow outdoors: May 5 to May 19Plant for fall: Jul 11 to Aug 1
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2
Start indoors: Apr 21 to May 5Transplant outside: Jun 23 to Jul 7Sow outdoors: Jun 23 to Jul 7
Start indoors: Apr 21 to May 5Transplant outside: Jun 9 to Jun 23
Sow outdoors: Apr 21 to May 12Plant for fall: Jun 27 to Jul 18
Sow outdoors: Apr 21 to May 12Plant for fall: Jul 25 to Aug 15
Sow outdoors: Apr 28 to Jun 9Plant for fall: Aug 8 to Aug 29
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 23Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23Plant for fall: Jul 11 to Jul 25
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 30
Sow outdoors: May 12 to Jun 9Plant for fall: Jun 27 to Jul 11
Sow outdoors: May 12 to Jun 9Plant for fall: Jul 11 to Jul 25
Sow outdoors: May 12 to Jun 2
Sow outdoors: May 19 to Jun 16Plant for fall: Jul 11 to Jul 25
Sow outdoors: May 19 to Jun 9Plant for fall: Jul 25 to Aug 15
Sow outdoors: Jun 9 to Jun 30
Sow outdoors: Jun 9 to Jun 23
Transplant outside: Jun 16 to Jul 7
Plant for fall: Sep 5 to Oct 10
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Centennial, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 10 – Mar 24 | May 5 – May 19 | — | — |
| Peppers | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Eggplant | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Tomatoes | Apr 7 – Apr 21 | Jun 9 – Jun 23 | — | — |
| Lettuce | Apr 7 – Apr 21 | May 12 – May 26 | May 5 – Jun 9 | Jul 25 – Aug 22 |
| Kale | Apr 7 – Apr 21 | May 5 – May 19 | May 5 – May 19 | Jul 11 – Aug 1 |
| Broccoli | Apr 7 – Apr 21 | May 19 – Jun 2 | — | — |
| Cabbage | Apr 7 – Apr 21 | May 12 – May 26 | — | — |
| Cauliflower | Apr 7 – Apr 21 | May 19 – Jun 2 | — | — |
| Okra | Apr 21 – May 5 | Jun 23 – Jul 7 | Jun 23 – Jul 7 | — |
| Basil | Apr 21 – May 5 | Jun 9 – Jun 23 | — | — |
| Peas | — | — | Apr 21 – May 12 | Jun 27 – Jul 18 |
| Spinach | — | — | Apr 21 – May 12 | Jul 25 – Aug 15 |
| Radishes | — | — | Apr 28 – Jun 9 | Aug 8 – Aug 29 |
| Cucumbers | May 5 – May 12 | Jun 16 – Jun 23 | Jun 9 – Jun 23 | — |
| Zucchini & Summer Squash | May 5 – May 12 | — | Jun 9 – Jun 23 | Jul 11 – Jul 25 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 109 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 5 – May 12 | — | Jun 9 – Jun 23 | — |
| Melons & Watermelon | May 5 – May 12 | Jun 16 – Jun 30 | — | — |
| Carrots | — | — | May 12 – Jun 9 | Jun 27 – Jul 11 |
| Beets | — | — | May 12 – Jun 9 | Jul 11 – Jul 25 |
| Potatoes | — | — | May 12 – Jun 2 | — |
| Swiss Chard | — | — | May 19 – Jun 16 | Jul 11 – Jul 25 |
| Cilantro | — | — | May 19 – Jun 9 | Jul 25 – Aug 15 |
| Green Beans | — | — | Jun 9 – Jun 30 | — |
| Sweet Corn | — | — | Jun 9 – Jun 23 | — |
| Sweet Potatoes Warning: Your frost-free season is about 109 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 16 – Jul 7 | — | — |
| Garlic | — | — | — | Sep 5 – Oct 10 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Centennial 1ne, WY weather station, 12 km away (elevation 8,169 ft (2,490 m)).
Frost dates near Centennial
- Laramie Jun 7 · Sep 4
- Jelm frost any month
- Bosler Jun 7 · Sep 4
- Rock River Jun 1 · Sep 8
- Elk Mountain May 28 · Sep 13
- Tie Siding May 31 · Sep 19
- Buford May 27 · Sep 19
- Medicine Bow Jun 1 · Sep 8
- Saratoga Jun 12 · Sep 7
- Encampment Jun 2 · Sep 12
Frequently asked questions
When is the last frost in Centennial, WY?
The median last spring frost in Centennial, WY is June 2. There is still about a 10% chance of frost after June 20, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Centennial, WY?
The median first fall frost is September 19, with about a 10% chance of frost before September 3.
How long is the growing season in Centennial, WY?
About 109 days between the median last spring frost and first fall frost.
What planting zone is Centennial, WY?
Centennial, WY is in USDA hardiness zone 5a.