USDA Hardiness Zone 10a
Frost Dates for 94941 — Mill Valley, California
Averages from Kentfield, Ca US, the nearest reporting station, 4.1 miles away.
Plant tender crops after January 16, and expect the first autumn freeze around December 18. That leaves about 334 frost-free days.
- Last spring frost
- January 16
- First fall frost
- December 18
- Growing season
- 334 days
- Hardiness zone
- 10a
50% probability
50% probability
frost-free
30 to 35°F annual low
Planting calendar for 94941
| When | What to do |
|---|---|
| November 7 – November 21 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| November 21 – December 5 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| December 19 – January 2 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| January 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by September 25 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by December 4 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| December 18 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 16 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Mill Valley, California are past their last freeze. Harvest before December 18, which leaves roughly 334 frost-free days.
ZIP 94941 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.