USDA Hardiness Zone 10a
Frost Dates for 91311 — Chatsworth, California
Averages from Northridge Cal State, Ca US, the nearest reporting station, 4.1 miles away.
Plant tender crops after January 2, and expect the first autumn freeze around January 1. That leaves about 365 frost-free days.
- Last spring frost
- January 2
- First fall frost
- January 1
- Growing season
- 365 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
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 20 observed
NOAA normal
When it snows in Chatsworth, California
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Woodland Hills Pierce College, Ca US, 5.5 miles away, 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 91311
| When | What to do |
|---|---|
| October 24 – November 7 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| November 7 – November 21 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| December 5 – December 19 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| January 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by October 9 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by December 18 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| January 1 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 January 2 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Chatsworth, California are past their last freeze. Harvest before January 1, which leaves roughly 365 frost-free days.
ZIP 91311 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.