Frost dates for Monrovia, CA
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 28
typical year
Safe to plant
May 27
frost is over in 9 of 10 years
First fall frost
November 15
typical year
Growing season
199 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 31 – Apr 14 | – |
| Spinach | – | Mar 17 – Apr 7 | Sep 20 – Oct 4 |
| Lettuce | – | Mar 31 – Apr 21 | Sep 20 – Oct 4 |
| Radishes | – | Mar 31 – May 12 | Oct 4 – 18 |
| Onions | – | Mar 31 – Apr 14 | – |
| Potatoes | – | Apr 7 – 21 | – |
| Carrots | – | Apr 7 – 28 | Aug 23 – Sep 6 |
| Beets | – | Mar 31 – Apr 14 | Sep 6 – 20 |
| Kale | Feb 17 – Mar 3 | Mar 31 – Apr 14 | Sep 6 – 20 |
| Broccoli | Feb 17 – Mar 3 | Apr 14 – 28 | Sep 6 – 20 |
| Cabbage | Feb 3 – 17 | Mar 31 – Apr 14 | Sep 6 – 20 |
| Garlic | – | – | Oct 4 – 25 |
| Warm-season crops | |||
| Tomatoes | Apr 1 – 15 | May 27 – Jun 10 | – |
| Peppers | Mar 25 – Apr 8 | Jun 3 – 17 | – |
| Cucumbers | – | May 27 – Jun 17 | – |
| Zucchini | – | May 27 – Jun 24 | – |
| Pumpkins | – | May 27 – Jun 17 | – |
| Green beans | – | May 27 – Sep 6 | – |
| Sweet corn | – | May 27 – Jun 24 | – |
| Basil | Apr 22 – May 6 | Jun 3 – 10 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 27 | April 28 | March 31 |
| Fall frost before | October 18 | November 15 | December 9 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 8 (May 10 in a late year), and the first one in fall around December 4.
Towns that use these dates
This is the nearest NOAA station with frost records for 4 towns.
Monrovia, Duarte, Sierra Madre, Bradbury
Where these dates come from
NOAA weather station MT WILSON CBS, CA US (USC00046006), 1991–2020 climate normals. It's the nearest station for 4 zip codes, all within 9 miles:
91008, 91010, 91016, 91024
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.