USDA Hardiness Zone 10a
Frost Dates for 91024 — Sierra Madre, California
Averages from Mt Wilson Cbs, Ca US, the nearest reporting station, 4.7 miles away.
Plant tender crops after April 28, and expect the first autumn freeze around November 15. That leaves about 199 frost-free days.
- Last spring frost
- April 28
- First fall frost
- November 15
- Growing season
- 199 days
- Hardiness zone
- 10a
50% probability
50% probability
frost-free
30 to 35°F annual low
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 6%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
1 of 18 observed
NOAA normal
When it snows in Sierra Madre, California
Measurable snow is rare here: only 1 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Mt Wilson Cbs, Ca US, so there is no typical first-snow date to plan around.
For a gardener, snow matters less than frost: a light snow on frozen ground changes nothing, while a hard frost on an unprotected bed ends the season. Use the frost dates above for planting and the snow dates for getting hoses drained, mulch down and tender pots indoors.
Planting calendar for 91024
| When | What to do |
|---|---|
| February 17 – March 3 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| March 3 – March 17 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| March 31 – April 14 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| April 28 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by August 23 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by November 1 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| November 15 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after April 28 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Sierra Madre, California are past their last freeze. Harvest before November 15, which leaves roughly 199 frost-free days.
ZIP 91024 sits in USDA hardiness zone 10a, meaning the average coldest night of the year falls between 30 to 35°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.