Round Mountain, CA frost dates
Last spring frostJun 3median date
First fall frostSep 14median date
Growing season103 daysfrost-free
Hardiness zone9aZone 9a
How Round Mountain compares
- In 8 years out of 10, the last spring frost in Round Mountain falls between May 15 and June 19, a 35-day window. The first fall frost falls between September 1 and September 27.
- The median last frost is 64 days later than the California median of Mar 31.
- Its 103-day growing season is longer than 3% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 92 days later than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 178 nights a year at or below 32°F.
- Nearby Redding, CA, 40 km away, gets only light, occasional frost, a reminder of how much elevation and distance from the coast matter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 15 |
| 50% (median) | June 3 |
| 10% (safe for tender plants) | June 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 1 |
| 50% (median) | September 14 |
| 90% (late) | September 27 |
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 Round Mountain, CA
Round Mountain, CA frost dates — last frost Jun 3, first frost Sep 14, zone 9a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 11 to Mar 25Transplant outside: May 6 to May 20
Start indoors: Mar 25 to Apr 8Transplant outside: Jun 17 to Jul 1
Start indoors: Mar 25 to Apr 8Transplant outside: Jun 17 to Jul 1
Start indoors: Apr 8 to Apr 22Transplant outside: Jun 10 to Jun 24
Start indoors: Apr 8 to Apr 22Transplant outside: May 13 to May 27Sow outdoors: May 6 to Jun 10Plant for fall: Jul 20 to Aug 17
Start indoors: Apr 8 to Apr 22Transplant outside: May 6 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 6 to Jul 27
Start indoors: Apr 8 to Apr 22Transplant outside: May 20 to Jun 3
Start indoors: Apr 8 to Apr 22Transplant outside: May 13 to May 27
Start indoors: Apr 8 to Apr 22Transplant outside: May 20 to Jun 3
Start indoors: Apr 22 to May 6Transplant outside: Jun 24 to Jul 8Sow outdoors: Jun 24 to Jul 8
Start indoors: Apr 22 to May 6Transplant outside: Jun 10 to Jun 24
Sow outdoors: Apr 22 to May 13Plant for fall: Jun 22 to Jul 13
Sow outdoors: Apr 22 to May 13Plant for fall: Jul 20 to Aug 10
Sow outdoors: Apr 29 to Jun 10Plant for fall: Aug 3 to Aug 24
Start indoors: May 6 to May 13Transplant outside: Jun 17 to Jun 24Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Transplant outside: Jun 17 to Jul 1
Sow outdoors: May 13 to Jun 10
Sow outdoors: May 13 to Jun 10Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 13 to Jun 3
Sow outdoors: May 20 to Jun 17Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 20 to Jun 10Plant for fall: Jul 20 to Aug 10
Sow outdoors: Jun 10 to Jul 1
Sow outdoors: Jun 10 to Jun 24
Transplant outside: Jun 17 to Jul 8
Plant for fall: Aug 31 to Oct 5
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Round Mountain, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 11 – Mar 25 | May 6 – May 20 | — | — |
| Peppers | Mar 25 – Apr 8 | Jun 17 – Jul 1 | — | — |
| Eggplant | Mar 25 – Apr 8 | Jun 17 – Jul 1 | — | — |
| Tomatoes | Apr 8 – Apr 22 | Jun 10 – Jun 24 | — | — |
| Lettuce | Apr 8 – Apr 22 | May 13 – May 27 | May 6 – Jun 10 | Jul 20 – Aug 17 |
| Kale | Apr 8 – Apr 22 | May 6 – May 20 | May 6 – May 20 | Jul 6 – Jul 27 |
| Broccoli | Apr 8 – Apr 22 | May 20 – Jun 3 | — | — |
| Cabbage | Apr 8 – Apr 22 | May 13 – May 27 | — | — |
| Cauliflower | Apr 8 – Apr 22 | May 20 – Jun 3 | — | — |
| Okra | Apr 22 – May 6 | Jun 24 – Jul 8 | Jun 24 – Jul 8 | — |
| Basil | Apr 22 – May 6 | Jun 10 – Jun 24 | — | — |
| Peas | — | — | Apr 22 – May 13 | Jun 22 – Jul 13 |
| Spinach | — | — | Apr 22 – May 13 | Jul 20 – Aug 10 |
| Radishes | — | — | Apr 29 – Jun 10 | Aug 3 – Aug 24 |
| Cucumbers | May 6 – May 13 | Jun 17 – Jun 24 | Jun 10 – Jun 24 | — |
| Zucchini & Summer Squash | May 6 – May 13 | — | Jun 10 – Jun 24 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 103 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 6 – May 13 | — | Jun 10 – Jun 24 | — |
| Melons & Watermelon | May 6 – May 13 | Jun 17 – Jul 1 | — | — |
| Carrots | — | — | May 13 – Jun 10 | — |
| Beets | — | — | May 13 – Jun 10 | Jul 6 – Jul 20 |
| Potatoes | — | — | May 13 – Jun 3 | — |
| Swiss Chard | — | — | May 20 – Jun 17 | Jul 6 – Jul 20 |
| Cilantro | — | — | May 20 – Jun 10 | Jul 20 – Aug 10 |
| Green Beans | — | — | Jun 10 – Jul 1 | — |
| Sweet Corn | — | — | Jun 10 – Jun 24 | — |
| Sweet Potatoes Warning: Your frost-free season is about 103 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 17 – Jul 8 | — | — |
| Garlic | — | — | — | Aug 31 – Oct 5 |
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 Burney, CA weather station, 26 km away (elevation 3,199 ft (975 m)).
Frost dates near Round Mountain
- Bella Vista Feb 8 · Dec 28
- Montgomery Creek Jun 3 · Sep 14
- Oak Run Mar 3 · Nov 21
- Whitmore Jun 9 · Sep 21
- Obrien Feb 8 · Dec 28
- Big Bend Jun 3 · Sep 14
- Burney Jun 3 · Sep 14
- Millville Mar 3 · Nov 21
- Shingletown Jun 9 · Sep 21
- Palo Cedro Mar 3 · Nov 21
Frequently asked questions
When is the last frost in Round Mountain, CA?
The median last spring frost in Round Mountain, CA is June 3. There is still about a 10% chance of frost after June 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Round Mountain, CA?
The median first fall frost is September 14, with about a 10% chance of frost before September 1.
How long is the growing season in Round Mountain, CA?
About 103 days between the median last spring frost and first fall frost.
What planting zone is Round Mountain, CA?
Round Mountain, CA is in USDA hardiness zone 9a.