California
Planting zones in Lake County, California
This county spans USDA zones 8b to 9b, so there is no single zone for Lake County and anyone who gives you one is rounding. 50% of its ZIP codes are zone 9a; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes Lake County, California as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.
Lake County does not have one planting answer
Its own weather stations disagree about 21 of the 32 crops in this table right now, so any single list would be wrong for part of the county. That is not a gap in the data — it is what the data says.
- Shortest season
- 209 days
CLEARLAKE 4 SE, CA US (USC00041806) - Longest season
- 279 days
CLOVERDALE, CA US (USC00041838)
70 days of growing season separate those two stations, and both serve ZIP codes in Lake County. The ZIP lookup above answers for one address instead of averaging a place that has no average.
Why the hardiness zone does not settle this
A USDA zone is a winter-minimum statistic. It was never a growing-season one, and it does not behave like one: within a single zone the growing season runs a median 54 days wider at the 10th–90th percentile, and annual growing degree days vary by 2.02×.
The zones also overlap rather than stack — 30% of zone 6b freezes before the median zone 6a station. The zone tells you what survives your winter; the station tells you what finishes before your autumn.
All 5 stations agreeAt least one station
Every one of the 5 NOAA stations serving this county counts April 10 – November 6 as growing season (210 days). Widening to any single station gives February 25 – December 3 (281 days).
That is a 71-day difference inside one county — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.
Which zone you are in depends where you are
Lake County covers 3 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 50% in zone 9a and wrong for the other 50%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 9a | 7 | 50% | |
| 8b | 4 | 29% | |
| 9b | 3 | 21% |
Zones are published per ZIP code, so yours is exact even though the county's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
Across the 5 NOAA stations serving this county. These are medians — half of years freeze later than the date shown — so treat the later end of each range as the cautious one.
The growing season runs 209–279 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 87.7–92.3 °F in June–August. That is past the point where tomato and pepper pollen fails and cool-season greens bolt, so in this county heat decides as much as frost does. Summer rain over the same months runs 0.3–0.6" across those 5 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 3% of it, so a summer garden here is watered rather than rained on. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 91 °F summer afternoon drying the soil faster than a cool one.
Every ZIP code in Lake County
Zones are published per ZIP code, not per county, so this is the exact answer rather than the county's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.
| ZIP code | USDA zone | Nearest NOAA station | Distance |
|---|---|---|---|
| 95422 | 9a | Clearlake 4 SE, CA | 9.5 km |
| 95423 | 9a | Clearlake 4 SE, CA | 16.8 km |
| 95426 | 9b | Clearlake 4 SE, CA | 17.6 km |
| 95435 | 8b | Cloverdale, CA | 26.8 km |
| 95443 | 9b | Clearlake 4 SE, CA | 20.5 km |
| 95451 | 9b | Clearlake 4 SE, CA | 19.2 km |
| 95453 | 8b | Ukiah Muni AP, CA | 24.1 km |
| 95457 | 9a | Clearlake 4 SE, CA | 1.6 km |
| 95458 | 9a | Clearlake 4 SE, CA | 27.5 km |
| 95461 | 9a | Calistoga, CA | 18.1 km |
| 95464 | 8b | Ukiah Muni AP, CA | 30.5 km |
| 95467 | 9a | Clearlake 4 SE, CA | 12.4 km |
| 95485 | 9a | Potter Valley Powerhouse, CA | 24.4 km |
| 95493 | 8b | Potter Valley Powerhouse, CA | 19.8 km |
ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.
When to start seeds in Lake County
Every date below is anchored on the last spring freeze at each station and reported as a range across all 5 of them, because no one station speaks for the county.
| Crop | Job | When | Offset |
|---|---|---|---|
| 🧅 Green Onions | Start indoors | January 5 – December 31 | 8 wk before |
| 🌶️ Peppers | Start indoors | January 5 – December 31 | 8 wk before |
| 🥦 Broccoli | Start indoors | January 14 – February 27 | 6 wk before |
| 🥬 Cabbage | Start indoors | January 14 – February 27 | 6 wk before |
| 🥬 Collards | Start indoors | January 14 – February 27 | 6 wk before |
| 🥬 Kale | Start indoors | January 14 – February 27 | 6 wk before |
| 🥬 Leaf Lettuce | Start indoors | January 14 – February 27 | 6 wk before |
| 🫛 Peas | Direct sow | January 14 – February 27 | 6 wk before |
| 🥬 Spinach | Direct sow | January 14 – February 27 | 6 wk before |
| 🍠 Sweet Potato | Start indoors | January 14 – February 27 | 6 wk before |
| 🍅 Tomatoes | Start indoors | January 14 – February 27 | 6 wk before |
| 🥬 Bok Choy | Start indoors | January 21 – March 6 | 5 wk before |
| 🥬 Kohlrabi | Start indoors | January 21 – March 6 | 5 wk before |
| 🥬 Swiss Chard | Start indoors | January 21 – March 6 | 5 wk before |
| 🥬 Arugula | Direct sow | January 28 – March 13 | 4 wk before |
| 🥬 Baby Salad Greens | Direct sow | January 28 – March 13 | 4 wk before |
| 🥕 Beets | Direct sow | January 28 – March 13 | 4 wk before |
| 🧅 Green Onions | Direct sow | January 28 – March 13 | 4 wk before |
| 🥬 Mustard Greens | Direct sow | January 28 – March 13 | 4 wk before |
| 🌶️ Okra | Start indoors | January 28 – March 13 | 4 wk before |
| 🌱 Radishes | Direct sow | January 28 – March 13 | 4 wk before |
| 🥔 Turnips | Direct sow | January 28 – March 13 | 4 wk before |
| 🥬 Cabbage | Set out | February 4 – March 20 | 3 wk before |
| 🥕 Carrots | Direct sow | February 4 – March 20 | 3 wk before |
| 🥬 Collards | Direct sow | February 4 – March 20 | 3 wk before |
| 🥬 Collards | Set out | February 4 – March 20 | 3 wk before |
| 🥒 Cucumbers | Start indoors | February 4 – March 20 | 3 wk before |
| 🧅 Green Onions | Set out | February 4 – March 20 | 3 wk before |
| 🥬 Kale | Direct sow | February 4 – March 20 | 3 wk before |
| 🥬 Kale | Set out | February 4 – March 20 | 3 wk before |
| 🥬 Kohlrabi | Direct sow | February 4 – March 20 | 3 wk before |
| 🥬 Kohlrabi | Set out | February 4 – March 20 | 3 wk before |
| 🥬 Leaf Lettuce | Direct sow | February 4 – March 20 | 3 wk before |
| 🎃 Pumpkins | Start indoors | February 4 – March 20 | 3 wk before |
| 🎃 Summer Squash | Start indoors | February 4 – March 20 | 3 wk before |
| 🎃 Winter Squash | Start indoors | February 4 – March 20 | 3 wk before |
| 🥒 Zucchini | Start indoors | February 4 – March 20 | 3 wk before |
| 🥬 Bok Choy | Direct sow | February 11 – March 27 | 2 wk before |
| 🥬 Bok Choy | Set out | February 11 – March 27 | 2 wk before |
| 🥦 Broccoli | Set out | February 11 – March 27 | 2 wk before |
| 🌿 Cilantro | Direct sow | February 11 – March 27 | 2 wk before |
| 🥬 Leaf Lettuce | Set out | February 11 – March 27 | 2 wk before |
| 🥬 Swiss Chard | Direct sow | February 11 – March 27 | 2 wk before |
| 🥬 Swiss Chard | Set out | February 11 – March 27 | 2 wk before |
| 🌿 Dill | Direct sow | February 18 – April 3 | 1 wk before |
| 🫘 Bush Beans | Direct sow | March 4 – April 17 | 1 wk after |
| 🥒 Cucumbers | Set out | March 4 – April 17 | 1 wk after |
| 🎃 Pumpkins | Direct sow | March 4 – April 17 | 1 wk after |
| 🎃 Pumpkins | Set out | March 4 – April 17 | 1 wk after |
| 🎃 Summer Squash | Direct sow | March 4 – April 17 | 1 wk after |
| 🎃 Summer Squash | Set out | March 4 – April 17 | 1 wk after |
| 🌽 Sweet Corn | Direct sow | March 4 – April 17 | 1 wk after |
| 🍅 Tomatoes | Set out | March 4 – April 17 | 1 wk after |
| 🎃 Winter Squash | Direct sow | March 4 – April 17 | 1 wk after |
| 🎃 Winter Squash | Set out | March 4 – April 17 | 1 wk after |
| 🥒 Zucchini | Direct sow | March 4 – April 17 | 1 wk after |
| 🥒 Zucchini | Set out | March 4 – April 17 | 1 wk after |
| 🥒 Cucumbers | Direct sow | March 11 – April 24 | 2 wk after |
| 🌶️ Okra | Direct sow | March 11 – April 24 | 2 wk after |
| 🌶️ Okra | Set out | March 11 – April 24 | 2 wk after |
| 🌶️ Peppers | Set out | March 11 – April 24 | 2 wk after |
| 🫘 Southern Peas | Direct sow | March 11 – April 24 | 2 wk after |
| 🍠 Sweet Potato | Set out | March 11 – April 24 | 2 wk after |
Offsets are published guidance; the dates they land on are computed from measured NOAA normals. The seed-starting tool does this for your own ZIP code and counts the days.
What survives the winter changes across Lake County
Zone 8b carries 54 of 74 perennial edibles; zone 9b carries 40. The best number is not always the warmest zone — the count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat, not to cold.
Hardiness ranges are a judgement, published by growers rather than measured; the zone they are compared against is measured. On a warm-end verdict, check with your local extension service — a coastal zone 8 and an inland zone 8 are not the same summer.
Cautious — shortens the seasonMedian across stationsOptimistic
- Last spring freeze
- Plan to April 30 to be careful. Median February 25 – April 10 across 5 stations; January 18 is the optimistic end.
- First fall freeze
- Plan to October 20 to be careful. Median November 6 – December 3 across 5 stations; December 25 is the optimistic end.
NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.
The 5 stations behind these numbers
All 5 NOAA stations whose normals this page quotes, spanning about 85 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole county.
A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.
These are the stations this county's ZIP codes actually cite as nearest — not a claim that each one sits inside its boundary, since a rural ZIP legitimately reaches over it. Every figure above comes from them, and each is named so you can check it.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Calistoga, CA | USC00041312 | March 2 | November 23 | 263 days |
| Clearlake 4 SE, CA | USC00041806 | April 10 | November 6 | 209 days |
| Cloverdale, CA | USC00041838 | February 25 | December 3 | 279 days |
| Potter Valley Powerhouse, CA | USC00047109 | April 8 | November 6 | 211 days |
| Ukiah Muni AP, CA | USW00023275 | March 5 | November 21 | 259 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Your own ZIP
Work out your own dates
This page describes a whole county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.
Other places to compare
Lake County sits in California. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.
More of California
- Tehama County, CA 7a, 7b, 9a, 9b
- Tuolumne County, CA 6a, 6b, 7b, 8a, 8b, 9a, 9b
- Trinity County, CA 7b, 8b, 9a
- Modoc County, CA 6b–7a
- Inyo County, CA 7a, 8a, 8b, 9a
- Mariposa County, CA 7a, 8a, 8b, 9a, 9b
- Mono County, CA 6a–7a
- Nevada County, CA 6b, 8b, 9a, 9b
- Sierra County, CA 6b, 7a, 8a, 8b, 9a
- Glenn County, CA 9a–9b
- Del Norte County, CA 8a, 9b
- Humboldt County, CA 9a–9b
Counties with the same zones — 8b–9b
Matched on the exact zone set, not a dominant zone, so the winter answer on these pages really is the same one as here.
Gear
If you want to act on this
Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.
- Shade clothSummer highs here average 91 °F, at or above the 90 °F point where lettuce and spinach bolt and tomato pollen fails.
- Row cover and frost clothThe season here closes at the first fall freeze dated above — a cover buys back some of those days at the end.
As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.
Sources
Where these numbers come from
Hardiness zones are the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. Freeze dates and growing-season lengths are NOAA 1991–2020 Climate Normals, taken per station and cited above by name and NOAA ID.
County boundaries come from the Census ZCTA-to-county relation, which is what places each ZIP code — and which treats parishes, boroughs and census areas as county equivalents. No station is chosen to represent this county: every range above is taken across all of them and the count is stated, because picking one would be a judgement dressed as a measurement.