Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 95443 — Glenhaven, CA

ZIP code 95443 (Glenhaven, Lake County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is April 10 and the first fall frost November 6.

Where ZIP 95443 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone9b25 to 30 °F
Coldest night−3.9 to −1.1 °C
Last frostApr 10
First frostNov 6
2012 zone8b

Was 8b on the 2012 map — a full zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Glenhaven, CA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Glenhaven, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 10median — 50% chance of a later frost
Safe for tender plantsApril 30only 10% chance of frost after
First fall frostNovember 6median — 10% chance by Oct 24
Growing season209 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 14 and returns around November 21.

From the NOAA station Clearlake 4 Se, CA — 12 miles away, elevation 1,348 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 95443

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 27 – Mar 13
SpinachSow outdoors · Feb 27 – Mar 20
Broccoli, cabbageStart indoors · Jan 30 – Feb 13
Broccoli, cabbageTransplant · Mar 20 – Apr 3
Onion setsPlant outdoors · Mar 13 – Mar 27
PotatoesPlant outdoors · Mar 20 – Apr 3
LettuceSow outdoors · Mar 13 – Mar 27
Carrots, beetsSow outdoors · Mar 20 – Apr 3
TomatoesStart indoors · Feb 13 – Feb 27
TomatoesTransplant · Apr 17 – May 1
Peppers, eggplantStart indoors · Jan 30 – Feb 13
Peppers, eggplantTransplant · Apr 24 – May 8
BeansSow outdoors · Apr 17 – May 1
Sweet cornSow outdoors · Apr 17 – May 1
Cucumbers, squashSow outdoors · Apr 17 – May 1
Fall lettuce, spinachSow outdoors · Sep 11 – Sep 25
GarlicPlant cloves · Oct 23 – Nov 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 10) and first fall frost (Nov 6) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 95443 came on Jan 29 — 7 days earlier than the 1991–2020 average (Feb 5).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Glenhaven, CA

The soil mapped at the center of ZIP 95443 is Millsholm — loam, well drained.

TextureLoama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Millsholm-Bressa-Hopland association, 30 to 50 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 95443; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Glenhaven, CA

Summer high91 °Faverage high, July
Winter low33 °Faverage low, January
Hot days66days a year at 90 °F or more
Freezing nights72nights a year at 32 °F or less
Growing degree days3,335base 50 °F — the season’s usable heat
Longest day14 h 55 mindaylight on June 21
Shortest day9 h 25 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation29.9 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 55 °F, low 33 °F 55°33° JanFebruary: average high 58 °F, low 34 °F 58°34° FebMarch: average high 62 °F, low 35 °F 62°35° MarApril: average high 66 °F, low 39 °F 66°39° AprMay: average high 73 °F, low 45 °F 73°45° MayJune: average high 83 °F, low 52 °F 83°52° JunJuly: average high 91 °F, low 56 °F 91°56° JulAugust: average high 91 °F, low 54 °F 91°54° AugSeptember: average high 85 °F, low 50 °F 85°50° SepOctober: average high 75 °F, low 43 °F 75°43° OctNovember: average high 63 °F, low 36 °F 63°36° NovDecember: average high 55 °F, low 33 °F 55°33° Dec

Precipitation by month inches

0″2″4″6″January: 6.19 in precipitation, 0.2 in snowfall 6.2 JanFebruary: 6.15 in precipitation, 0.1 in snowfall 6.2 FebMarch: 3.99 in precipitation, 0.1 in snowfall 4.0 MarApril: 1.99 in precipitation 2.0 AprMay: 1.16 in precipitation 1.2 MayJune: 0.23 in precipitation 0.2 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.09 in precipitation 0.1 AugSeptember: 0.17 in precipitation 0.2 SepOctober: 0.91 in precipitation 0.9 OctNovember: 2.89 in precipitation 2.9 NovDecember: 6.08 in precipitation 6.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Clearlake 4 Se, CA (12 mi away); precipitation: Clearlake 4 Se, CA (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

7 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

954589a
Lucerne, CA · 5 mi
954239a
Clearlake Oaks, CA · 6 mi
954229a
Clearlake, CA · 7 mi
954249a
Clearlake Park, CA · 8 mi
954648b
Nice, CA · 8 mi
954358b
Finley, CA · 8 mi
954519b
Kelseyville, CA · 9 mi
954538b
Lakeport, CA · 11 mi

California planting zones →

Questions about 95443

What planting zone is ZIP code 95443?

ZIP code 95443 (Glenhaven, CA) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Glenhaven, CA?

The median last spring frost (32 °F) near 95443 is April 10; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Clearlake 4 Se station.

When is the first frost in Glenhaven, CA?

The median first fall frost near 95443 is November 6, giving a median frost-free growing season of 209 days.

When should I plant tomatoes in 95443?

Start tomato seeds indoors around Feb 13 – Feb 27 and set transplants outside around Apr 17 – May 1, one to three weeks after the median last frost.

How much rain and snow does 95443 get?

About 29.9 inches of precipitation a year (NOAA 1991–2020 normals, Clearlake 4 Se station).

How hot do summers get in Glenhaven, CA?

The average high peaks at 91 °F in July, with about 66 days a year at 90 °F or more.

What kind of soil does 95443 have?

The USDA soil survey maps Millsholm at the center of ZIP 95443: loam, well drained, pH about 6.5 (neutral).

Did spring come early in Glenhaven, CA in 2026?

Spring leaf-out near 95443 came on Jan 29 in 2026, 7 days earlier than the 1991–2020 average (Feb 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Glenhaven, CA?

Intermediate onions: the longest day near 95443 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 95443 change?

Yes. The 2012 USDA map put 95443 in zone 8b; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.