Riverside, California planting calendar and frost dates
Riverside is in USDA hardiness zone 10a. The last spring frost typically comes around January 9 and the first fall frost around December 30, giving about 362 frost-free days a year.
- Typical last frost
- January 9
- Typical first frost
- December 30
- Frost-free season
- 362 days
Frost dates in Riverside
Last spring frost
- December 16Risky: frost later than this in 9 years out of 10
- January 9Typical: a later frost in half of years
- February 21Safe: a later frost only 1 year in 10
First fall frost
- December 5Risky: frost earlier than this 1 year in 10
- December 30Typical: an earlier frost in half of years
- New yearLate: in about 1 year in 10, the first frost waits until after December 31
The growing season between the typical last and first frosts is about 362 days. Frost here means a low of 32°F at the weather station.
NOAA U.S. Climate Normals 1991-2020 for Riverside Muni Airport, 2.4 miles W of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Riverside
January
Start indoors: basil, eggplants, peppers, tomatoes
Plant or sow outdoors: asparagus, avocados, beets, carrots, cauliflower, chives, cilantro, dahlias, dill, figs, garden mums, ginger, gladioli, grapes, green onions, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, swiss chard, thyme
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
February
Start indoors: basil, cantaloupes, celery, cucumbers, pumpkins, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: avocados, garden mums, green onions, st. augustinegrass
March
Start indoors: cosmos, cucumbers, okra, pumpkins, winter squash, zucchini
Plant or sow outdoors: basil, cantaloupes, cucumbers, eggplants, green beans, peppers, pumpkins, st. augustinegrass, tomatoes, watermelons, winter squash, zucchini
April
Plant or sow outdoors: bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, green beans, okra, peanuts, peppers, pumpkins, sweet potatoes, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
May
Start indoors: zinnias
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, okra, peanuts, sweet potatoes, zoysiagrass
June
Plant or sow outdoors: bermudagrass, centipedegrass, zinnias, zoysiagrass
September
Start indoors: onions
Plant for fall: brussels sprouts, collard greens, cucumbers, lettuce, peppers, potatoes, sweet corn, swiss chard, tomatoes
October
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
Plant for fall: bearded irises, beets, broccoli, cabbages, carrots, cauliflower, collard greens, cucumbers, daylilies, green beans, kale, lettuce, peas, peppers, radishes, snapdragons, spinach, sweet corn, swiss chard, turnips, zucchini
November
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, cilantro, collard greens, ginger, kale, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard
Plant or sow outdoors: asparagus, black-eyed susans, blueberries, garlic, grapes, grass seed, green onions, hollyhocks, kentucky bluegrass, onions, peas, poppies, raspberries, rhubarb, strawberries, sweet peas, tall fescue, turnips, wildflowers
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, kentucky bluegrass, lettuce, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, snapdragons, spinach, tall fescue, tulips, turnips
December
Start indoors: cilantro, marigolds, nasturtiums, ranunculus, spinach, swiss chard
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, green onions, hollyhocks, kale, kentucky bluegrass, leeks, lettuce, onions, parsley, peas, peppers, poppies, potatoes, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, sweet peas, swiss chard, tall fescue, turnips, wildflowers
Plant for fall: crocuses, daffodils, daylilies, garlic, grass seed, hostas, hyacinths, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, saffron, tall fescue, tulips
Frost dates and zones by ZIP code in Riverside
All 7 of Riverside's main ZIP codes take their frost dates from Riverside Muni Airport, so the dates on this page apply across the city. The hardiness zone is 10a in 92501, 92503, 92504, 92505, 92506, 92507, and 9b in 92508.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 92501 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92503 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92504 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92505 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92506 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92507 | 10a | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
| 92508 | 9b | Riverside Muni Airport, 2.4 mi W | Jan 9 | Dec 30 |
Riverside Muni Airport also supplies the frost dates for Fontana and Jurupa Valley, so their planting calendars match Riverside's.
Planting dates for popular crops in Riverside
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Jan 23 to Feb 6 | Mar 20 to Apr 3 | Sep 16 to 23 |
| Strawberries | — | Nov 28 to Dec 12 | — |
| Lettuce | Nov 14 to 28 | Jan 2 to 16 | Sep 30 to Nov 4 |
| Cilantro | Nov 28 to Dec 12 | Jan 9 to 16 | — |
| Basil | Jan 30 to Feb 13 | Mar 20 to 27 | — |
| Potatoes | — | Dec 19 to 26 | Sep 9 to 16 |
| Garlic | — | Nov 28 to Dec 12 | Dec 30 to Jan 13 |
| Onions | Sep 19 to Oct 31 | Dec 12 to 26 | — |
| Cucumbers | Feb 20 to Mar 6 | Mar 20 to Apr 3 | Sep 30 to Oct 14 |
| Pumpkins | Feb 20 to Mar 6 | Mar 20 to Apr 3 | — |
| Peppers | Jan 2 to 30 | Mar 20 to Apr 3 | Sep 9 to Oct 7 |
| Carrots | — | Dec 19 to Jan 9 | Oct 7 to 28 |
| Sweet Potatoes | — | Apr 30 to May 7 | — |
| Watermelons | Feb 13 to 27 | Mar 20 to Apr 3 | — |
| Sweet Corn | — | Jan 9 to 23 | Sep 23 to Oct 7 |
| Green Beans | — | Mar 20 to Apr 3 | Oct 7 to 14 |
| Zucchini | Feb 20 to Mar 6 | Mar 20 to Apr 3 | Oct 7 to 21 |
| Broccoli | Oct 24 to Nov 14 | Dec 12 to 26 | Oct 14 to Nov 11 |
| Peas | — | Nov 28 to Dec 12 | Oct 7 to 21 |
| Spinach | Nov 28 to Dec 5 | Jan 2 to 16 | Oct 21 to Nov 25 |
| Sunflowers | — | Jan 9 to 30 | — |
| Zinnias | May 4 to 11 | Jun 1 to 15 | — |
| Tulips | — | — | Nov 18 to Jan 13 |
| Daffodils | — | — | Nov 18 to Dec 30 |
| Grass Seed | — | Nov 28 to Dec 12 | Nov 18 to Dec 2 |
Nearby cities
- Jurupa Valley, CA zone 10a, last frost Jan 9
- Colton, CA zone 10a, last frost Jan 27
- Moreno Valley, CA zone 9b, last frost Jan 27
- Eastvale, CA zone 10a, last frost Jan 17
- Corona, CA zone 10a, last frost Jan 17
- Rialto, CA zone 10a, last frost Jan 27
Planting in CaliforniaAbout zone 10aPrintable calendar for Riverside
Questions
When is the last frost in Riverside?
Around January 9 in a typical year, based on NOAA's 1991-2020 records for Riverside Muni Airport. There is still a 1 in 10 chance of frost after February 21.
What planting zone is Riverside in?
USDA hardiness zone 10a (2023 map), with parts of the city in zone 9b. The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Riverside?
Start seeds indoors January 23 to February 6 and set plants out March 20 to April 3.
When is the first frost in Riverside?
Around December 30 in a typical year, and before December 5 about 1 year in 10.