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

Planting zone for 95416 — Boyes Hot Springs, CA

ZIP code 95416 (Boyes Hot Springs, Sonoma County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is March 2 and the first fall frost November 27.

Where ZIP 95416 is

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 frostMar 2
First frostNov 27
2012 zone9b

Same zone as on the 2012 map. 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 Boyes Hot Springs, 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 Boyes Hot Springs, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 2median — 50% chance of a later frost
Safe for tender plantsApril 5only 10% chance of frost after
First fall frostNovember 27median — 10% chance by Nov 6
Growing season270 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 20 and returns around December 14.

From the NOAA station Sonoma, CA — 2 miles away, elevation 98 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 95416

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 19 – Feb 2
SpinachSow outdoors · Jan 19 – Feb 9
Broccoli, cabbageStart indoors · Dec 22 – Jan 5
Broccoli, cabbageTransplant · Feb 9 – Feb 23
Onion setsPlant outdoors · Feb 2 – Feb 16
PotatoesPlant outdoors · Feb 9 – Feb 23
LettuceSow outdoors · Feb 2 – Feb 16
Carrots, beetsSow outdoors · Feb 9 – Feb 23
TomatoesStart indoors · Jan 5 – Jan 19
TomatoesTransplant · Mar 9 – Mar 23
Peppers, eggplantStart indoors · Dec 22 – Jan 5
Peppers, eggplantTransplant · Mar 16 – Mar 30
BeansSow outdoors · Mar 9 – Mar 23
Sweet cornSow outdoors · Mar 9 – Mar 23
Cucumbers, squashSow outdoors · Mar 9 – Mar 23
Fall lettuce, spinachSow outdoors · Oct 2 – Oct 16
GarlicPlant cloves · Nov 13 – Dec 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 2) and first fall frost (Nov 27) 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 95416 came on Jan 29 — about the same time as the 1991–2020 average (Jan 30).

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 Boyes Hot Springs, CA

The soil mapped at the center of ZIP 95416 is Zamora — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Zamora silty clay loam, moist, 0 to 2 percent slopes, MLRA 14.

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 95416; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Boyes Hot Springs, CA

Summer high86 °Faverage high, July
Winter low38 °Faverage low, January
Hot days44days a year at 90 °F or more
Freezing nights21nights a year at 32 °F or less
Growing degree days3,608base 50 °F — the season’s usable heat
Longest day14 h 50 mindaylight on June 21
Shortest day9 h 30 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation28.4 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 57 °F, low 38 °F 57°38° JanFebruary: average high 62 °F, low 40 °F 62°40° FebMarch: average high 65 °F, low 42 °F 65°42° MarApril: average high 69 °F, low 44 °F 69°44° AprMay: average high 75 °F, low 48 °F 75°48° MayJune: average high 83 °F, low 51 °F 83°51° JunJuly: average high 86 °F, low 54 °F 86°54° JulAugust: average high 86 °F, low 53 °F 86°53° AugSeptember: average high 85 °F, low 51 °F 85°51° SepOctober: average high 78 °F, low 47 °F 78°47° OctNovember: average high 65 °F, low 42 °F 65°42° NovDecember: average high 57 °F, low 38 °F 57°38° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.47 in precipitation 5.5 JanFebruary: 5.42 in precipitation 5.4 FebMarch: 3.84 in precipitation 3.8 MarApril: 1.78 in precipitation 1.8 AprMay: 1.03 in precipitation 1.0 MayJune: 0.32 in precipitation 0.3 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.06 in precipitation 0.1 AugSeptember: 0.07 in precipitation 0.1 SepOctober: 1.52 in precipitation 1.5 OctNovember: 3.01 in precipitation 3.0 NovDecember: 5.83 in precipitation 5.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Sonoma, CA (2 mi away); precipitation: Sonoma, CA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

954339b
El Verano, CA · 1 mi
954319b
Eldridge, CA · 3 mi
954879b
Vineburg, CA · 4 mi
954769b
Sonoma, CA · 4 mi
954429b
Glen Ellen, CA · 5 mi
949549b
Petaluma, CA · 7 mi
945999b
Yountville, CA · 8 mi
954529b
Kenwood, CA · 8 mi

California planting zones →

Questions about 95416

What planting zone is ZIP code 95416?

ZIP code 95416 (Boyes Hot Springs, 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 Boyes Hot Springs, CA?

The median last spring frost (32 °F) near 95416 is March 2; after April 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sonoma station.

When is the first frost in Boyes Hot Springs, CA?

The median first fall frost near 95416 is November 27, giving a median frost-free growing season of 270 days.

When should I plant tomatoes in 95416?

Start tomato seeds indoors around Jan 5 – Jan 19 and set transplants outside around Mar 9 – Mar 23, one to three weeks after the median last frost.

How much rain and snow does 95416 get?

About 28.4 inches of precipitation a year (NOAA 1991–2020 normals, Sonoma station).

How hot do summers get in Boyes Hot Springs, CA?

The average high peaks at 86 °F in July, with about 44 days a year at 90 °F or more.

What kind of soil does 95416 have?

The USDA soil survey maps Zamora at the center of ZIP 95416: silty clay loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Boyes Hot Springs, CA in 2026?

Spring leaf-out near 95416 came on Jan 29 in 2026, about the same as the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Boyes Hot Springs, CA?

Intermediate onions: the longest day near 95416 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.