Alturas, CA frost dates
Last spring frostJun 3median date
First fall frostSep 13median date
Growing season102 daysfrost-free
Hardiness zone6bZone 6b
How Alturas compares
- In 8 years out of 10, the last spring frost in Alturas falls between May 15 and June 26, a 42-day window. The first fall frost falls between August 27 and September 28.
- The median last frost is 64 days later than the California median of Mar 31.
- Its 102-day growing season is among the shortest of the 636 California places with a regular frost season.
- The last frost is 42 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 204 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 15 |
| 50% (median) | June 3 |
| 10% (safe for tender plants) | June 26 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 27 |
| 50% (median) | September 13 |
| 90% (late) | September 28 |
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 Alturas, CA
Alturas, CA frost dates — last frost Jun 3, first frost Sep 13, zone 6b. whenisthelastfrost.com
Crop
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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 19 to Aug 16
Start indoors: Apr 8 to Apr 22Transplant outside: May 6 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 5 to Jul 26
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 21 to Jul 12
Sow outdoors: Apr 22 to May 13Plant for fall: Jul 19 to Aug 9
Sow outdoors: Apr 29 to Jun 10Plant for fall: Aug 2 to Aug 23
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 5 to Jul 19
Sow outdoors: May 13 to Jun 3
Sow outdoors: May 20 to Jun 17Plant for fall: Jul 5 to Jul 19
Sow outdoors: May 20 to Jun 10Plant for fall: Jul 19 to Aug 9
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 30 to Oct 4
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Alturas, 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 19 – Aug 16 |
| Kale | Apr 8 – Apr 22 | May 6 – May 20 | May 6 – May 20 | Jul 5 – Jul 26 |
| 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 21 – Jul 12 |
| Spinach | — | — | Apr 22 – May 13 | Jul 19 – Aug 9 |
| Radishes | — | — | Apr 29 – Jun 10 | Aug 2 – Aug 23 |
| 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 102 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 5 – Jul 19 |
| Potatoes | — | — | May 13 – Jun 3 | — |
| Swiss Chard | — | — | May 20 – Jun 17 | Jul 5 – Jul 19 |
| Cilantro | — | — | May 20 – Jun 10 | Jul 19 – Aug 9 |
| Green Beans | — | — | Jun 10 – Jul 1 | — |
| Sweet Corn | — | — | Jun 10 – Jun 24 | — |
| Sweet Potatoes Warning: Your frost-free season is about 102 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 17 – Jul 8 | — | — |
| Garlic | — | — | — | Aug 30 – Oct 4 |
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 Alturas, CA weather station, about 1 km away (elevation 4,377 ft (1,334 m)).
Frost dates near Alturas
- Likely Jun 14 · Sep 18
- Canby Jun 1 · Sep 16
- Davis Creek May 26 · Oct 1
- Cedarville May 15 · Oct 1
- Lake City May 15 · Oct 1
- Eagleville Jun 14 · Sep 18
- Adin May 28 · Sep 29
- Fort Bidwell May 26 · Oct 1
- Madeline Jun 14 · Sep 18
- Termo May 28 · Sep 29
Frequently asked questions
When is the last frost in Alturas, CA?
The median last spring frost in Alturas, CA is June 3. There is still about a 10% chance of frost after June 26, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Alturas, CA?
The median first fall frost is September 13, with about a 10% chance of frost before August 27.
How long is the growing season in Alturas, CA?
About 102 days between the median last spring frost and first fall frost.
What planting zone is Alturas, CA?
Alturas, CA is in USDA hardiness zone 6b.