Hornbrook, CA frost dates
Last spring frostMay 12median date
First fall frostOct 8median date
Growing season149 daysfrost-free
Hardiness zone8aZone 8a
How Hornbrook compares
- In 8 years out of 10, the last spring frost in Hornbrook falls between April 26 and June 1, a 36-day window. The first fall frost falls between September 24 and October 22.
- The median last frost is 42 days later than the California median of Mar 31.
- Its 149-day growing season is longer than 15% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 44 days later than the zone 8a median of Mar 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8a chart.
- The weather station records an average of 137 nights a year at or below 32°F.
- Compared with Medford, OR, 53 km away, the last frost here is 34 days later than there and the growing season is 55 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 26 |
| 50% (median) | May 12 |
| 10% (safe for tender plants) | June 1 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 24 |
| 50% (median) | October 8 |
| 90% (late) | October 22 |
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 Hornbrook, CA
Hornbrook, CA frost dates — last frost May 12, first frost Oct 8, zone 8a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 17 to Mar 3Transplant outside: Apr 14 to Apr 28
Start indoors: Mar 3 to Mar 17Transplant outside: May 26 to Jun 9
Start indoors: Mar 3 to Mar 17Transplant outside: May 26 to Jun 9
Start indoors: Mar 17 to Mar 31Transplant outside: May 19 to Jun 2
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 21 to May 5Sow outdoors: Apr 14 to May 19Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 14 to Apr 28Sow outdoors: Apr 14 to Apr 28Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 28 to May 12Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 21 to May 5Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 28 to May 12Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 31 to Apr 14Transplant outside: Jun 2 to Jun 16Sow outdoors: Jun 2 to Jun 16
Start indoors: Mar 31 to Apr 14Transplant outside: May 19 to Jun 2
Sow outdoors: Mar 31 to Apr 21Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 31 to Apr 21Plant for fall: Aug 13 to Sep 3
Sow outdoors: Apr 7 to May 19Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 14 to Apr 21Transplant outside: May 26 to Jun 2Sow outdoors: May 19 to Jun 2Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 14 to Apr 21Sow outdoors: May 19 to Jun 2Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 14 to Apr 21Sow outdoors: May 19 to Jun 2
Start indoors: Apr 14 to Apr 21Transplant outside: May 26 to Jun 9
Sow outdoors: Apr 21 to May 19Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 21 to May 19Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 21 to May 12
Sow outdoors: Apr 28 to May 26Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 28 to May 19Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 19 to Jun 9Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 19 to Jun 2
Transplant outside: May 26 to Jun 16
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Hornbrook, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 17 – Mar 3 | Apr 14 – Apr 28 | — | — |
| Peppers | Mar 3 – Mar 17 | May 26 – Jun 9 | — | — |
| Eggplant | Mar 3 – Mar 17 | May 26 – Jun 9 | — | — |
| Tomatoes | Mar 17 – Mar 31 | May 19 – Jun 2 | — | — |
| Lettuce | Mar 17 – Mar 31 | Apr 21 – May 5 | Apr 14 – May 19 | Aug 13 – Sep 10 |
| Kale | Mar 17 – Mar 31 | Apr 14 – Apr 28 | Apr 14 – Apr 28 | Jul 30 – Aug 20 |
| Broccoli | Mar 17 – Mar 31 | Apr 28 – May 12 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 17 – Mar 31 | Apr 21 – May 5 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 17 – Mar 31 | Apr 28 – May 12 | — | Jul 2 – Jul 23 |
| Okra | Mar 31 – Apr 14 | Jun 2 – Jun 16 | Jun 2 – Jun 16 | — |
| Basil | Mar 31 – Apr 14 | May 19 – Jun 2 | — | — |
| Peas | — | — | Mar 31 – Apr 21 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 31 – Apr 21 | Aug 13 – Sep 3 |
| Radishes | — | — | Apr 7 – May 19 | Aug 27 – Sep 17 |
| Cucumbers | Apr 14 – Apr 21 | May 26 – Jun 2 | May 19 – Jun 2 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 14 – Apr 21 | — | May 19 – Jun 2 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 14 – Apr 21 | — | May 19 – Jun 2 | — |
| Melons & Watermelon | Apr 14 – Apr 21 | May 26 – Jun 9 | — | — |
| Carrots | — | — | Apr 21 – May 19 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 21 – May 19 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 21 – May 12 | — |
| Swiss Chard | — | — | Apr 28 – May 26 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 28 – May 19 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 19 – Jun 9 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 19 – Jun 2 | — |
| Sweet Potatoes | — | May 26 – Jun 16 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Montague Siskiyou Co Ap, CA weather station, 15 km away (elevation 2,635 ft (803 m)).
Frost dates near Hornbrook
- Montague May 12 · Oct 8
- Yreka Apr 30 · Oct 18
- Klamath River Apr 30 · Oct 18
- Grenada Apr 30 · Oct 18
- Scott Bar Apr 30 · Oct 18
- Fort Jones Apr 30 · Oct 18
- Gazelle Apr 30 · Oct 18
- Dorris Jun 5 · Sep 20
- Macdoel Jun 5 · Sep 20
- Greenview May 20 · Oct 5
Frequently asked questions
When is the last frost in Hornbrook, CA?
The median last spring frost in Hornbrook, CA is May 12. There is still about a 10% chance of frost after June 1, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Hornbrook, CA?
The median first fall frost is October 8, with about a 10% chance of frost before September 24.
How long is the growing season in Hornbrook, CA?
About 149 days between the median last spring frost and first fall frost.
What planting zone is Hornbrook, CA?
Hornbrook, CA is in USDA hardiness zone 8a.