Last frost date in Riverside, CA
The average last frost in Riverside is January 9. By February 25 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about December 25, which leaves 353 frost-free days. An early freeze before December 1 happens one year in ten.
- Safe after (10% risk)
- Feb 25
- Average first frost
- Dec 25
- Frost-free season
- 353 days
- Hard freeze (28°F) ends
- Dec 31
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:24 UTC
- ThuOct 2256°
- FriOct 2354°
- SatOct 2456°
- SunOct 2558°
- MonOct 2658°
- TueOct 2757°
Planting calendar for Riverside
Windows count forward or back from the average frost dates above. Click a crop for dates across California.
TomatoesFeb 15–Mar 1
PumpkinsFeb 15–Mar 1
SunflowersFeb 15–Mar 8
CucumbersFeb 22–Mar 1
CornFeb 15–Mar 1
Sweet potatoesFeb 15–Mar 1
WatermelonFeb 15–Mar 1
Green beansFeb 15–Mar 8
ZucchiniFeb 15–Mar 1
OkraFeb 15–Mar 1
PeppersFeb 15–Mar 1
BasilFeb 15–Mar 1
Butternut squashFeb 15–Mar 1
CantaloupeFeb 15–Mar 1
EggplantFeb 15–Mar 1
PotatoesDec 12–Dec 26
OnionsNov 28–Dec 19
CarrotsDec 19–Jan 23
LettuceDec 26–Jan 16
BroccoliDec 12–Dec 26
BeetsDec 12–Jan 23
PeasNov 28–Dec 12
CabbageDec 12–Dec 26
RadishesDec 5–Jan 16
Brussels sproutsDec 26–Jan 9
SpinachNov 28–Dec 19
CilantroDec 26–Jan 16
KaleDec 12–Dec 26
Collard greensDec 12–Dec 26
TurnipsDec 12–Dec 26
DillJan 9–Jan 23
CeleryJan 16–Jan 23
CauliflowerDec 26–Jan 9
LeeksDec 26–Jan 9
Swiss chardDec 26–Jan 23
ParsleyDec 26–Jan 16
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesDec 12–Dec 26
AsparagusDec 12–Dec 26Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Dec 16 | Jan 9 | Feb 25 | Dec 1 | Dec 25 | Jan 27 |
| Hard freeze, 28°F | Dec 13 | Dec 31 | Jan 16 | Nov 30 | Dec 29 | Jan 13 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Riverside Fire Station 3 (USC00047470) sits 0.9 miles from the center of Riverside at 840 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Riverside, CA?
The average last frost date in Riverside is January 9, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after February 25.
When is the first frost in Riverside?
The first frost in fall usually comes around December 25. One year in ten it arrives before December 1.
How long is the growing season in Riverside?
About 353 days between the average last and first frost.
When should I plant tomatoes in Riverside?
Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.
Nearby in California
- Jurupa ValleyJan 9
- BloomingtonJan 10
- ColtonJan 10
- NorcoJan 17
- Moreno ValleyJan 27
- EastvaleJan 17
- Loma LindaJan 27
- CoronaJan 17
- RialtoJan 10
- FontanaJan 4
- Temescal ValleyJan 28
- OntarioJan 4