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

Planting zone for 93668 — Tranquillity, CA

ZIP code 93668 (Tranquillity, Fresno County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is February 27 and the first fall frost November 26.

Where ZIP 93668 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.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostFeb 27
First frostNov 26
2012 zone9a

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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tranquillity, 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 Tranquillity, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 27median — 50% chance of a later frost
Safe for tender plantsApril 13only 10% chance of frost after
First fall frostNovember 26median — 10% chance by Nov 8
Growing season271 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 21 and returns around December 9.

From the NOAA station Five Points 5 Ssw, CA — 22 miles away, elevation 285 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 93668

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 16 – Jan 30
SpinachSow outdoors · Jan 16 – Feb 6
Broccoli, cabbageStart indoors · Dec 19 – Jan 2
Broccoli, cabbageTransplant · Feb 6 – Feb 20
Onion setsPlant outdoors · Jan 30 – Feb 13
PotatoesPlant outdoors · Feb 6 – Feb 20
LettuceSow outdoors · Jan 30 – Feb 13
Carrots, beetsSow outdoors · Feb 6 – Feb 20
TomatoesStart indoors · Jan 2 – Jan 16
TomatoesTransplant · Mar 6 – Mar 20
Peppers, eggplantStart indoors · Dec 19 – Jan 2
Peppers, eggplantTransplant · Mar 13 – Mar 27
BeansSow outdoors · Mar 6 – Mar 20
Sweet cornSow outdoors · Mar 6 – Mar 20
Cucumbers, squashSow outdoors · Mar 6 – Mar 20
Fall lettuce, spinachSow outdoors · Oct 1 – Oct 15
GarlicPlant cloves · Nov 12 – Dec 17
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 27) and first fall frost (Nov 26) 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 93668 came on Feb 1 — about the same time as the 1991–2020 average (Feb 1).

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 Tranquillity, CA

The soil mapped at the center of ZIP 93668 is Tachi — clay, very poorly drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH8.0alkaline; most vegetables like 6.0–7.0
DrainageVery poorly drainedconsider raised beds
Organic matter2%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Tachi clay, 0 to 1 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 93668; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tranquillity, CA

Summer high99 °Faverage high, July
Winter low37 °Faverage low, December
Hot days114days a year at 90 °F or more
Freezing nights23nights a year at 32 °F or less
Growing degree days5,527base 50 °F — the season’s usable heat
Longest day14 h 40 mindaylight on June 21
Shortest day9 h 39 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation10.7 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 59 °F, low 38 °F 59°38° JanFebruary: average high 65 °F, low 40 °F 65°40° FebMarch: average high 71 °F, low 44 °F 71°44° MarApril: average high 77 °F, low 47 °F 77°47° AprMay: average high 86 °F, low 54 °F 86°54° MayJune: average high 94 °F, low 58 °F 94°58° JunJuly: average high 99 °F, low 63 °F 99°63° JulAugust: average high 98 °F, low 62 °F 98°62° AugSeptember: average high 94 °F, low 58 °F 94°58° SepOctober: average high 82 °F, low 50 °F 82°50° OctNovember: average high 69 °F, low 41 °F 69°41° NovDecember: average high 59 °F, low 37 °F 59°37° Dec

Precipitation by month inches

0″1″2″January: 1.94 in precipitation 1.9 JanFebruary: 1.93 in precipitation 1.9 FebMarch: 1.94 in precipitation 1.9 MarApril: 1.10 in precipitation 1.1 AprMay: 0.54 in precipitation 0.5 MayJune: 0.12 in precipitation 0.1 JunJuly: 0.03 in precipitation 0.0 JulAugust: 0.01 in precipitation 0.0 AugSeptember: 0.07 in precipitation 0.1 SepOctober: 0.55 in precipitation 0.6 OctNovember: 0.79 in precipitation 0.8 NovDecember: 1.64 in precipitation 1.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Five Points 5 Ssw, CA (22 mi away); precipitation: Helm 2.7 Nne, CA (13 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

936609a
San Joaquin, CA · 8 mi
936409a
Mendota, CA · 8 mi
936309a
Kerman, CA · 10 mi
936089b
Cantua Creek, CA · 11 mi
936279a
Helm, CA · 14 mi
936069a
Biola, CA · 18 mi
936379a
Madera, CA · 19 mi
936229b
Firebaugh, CA · 20 mi

California planting zones →

Questions about 93668

What planting zone is ZIP code 93668?

ZIP code 93668 (Tranquillity, CA) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Tranquillity, CA?

The median last spring frost (32 °F) near 93668 is February 27; after April 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Five Points 5 Ssw station.

When is the first frost in Tranquillity, CA?

The median first fall frost near 93668 is November 26, giving a median frost-free growing season of 271 days.

When should I plant tomatoes in 93668?

Start tomato seeds indoors around Jan 2 – Jan 16 and set transplants outside around Mar 6 – Mar 20, one to three weeks after the median last frost.

How much rain and snow does 93668 get?

About 10.7 inches of precipitation a year (NOAA 1991–2020 normals, Helm 2.7 Nne station).

How hot do summers get in Tranquillity, CA?

The average high peaks at 99 °F in July, with about 114 days a year at 90 °F or more.

What kind of soil does 93668 have?

The USDA soil survey maps Tachi at the center of ZIP 93668: clay, very poorly drained, pH about 8.0 (alkaline).

Did spring come early in Tranquillity, CA in 2026?

Spring leaf-out near 93668 came on Feb 1 in 2026, about the same as the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tranquillity, CA?

Intermediate onions: the longest day near 93668 is 14 h 40 min, so day-neutral types bulb best; long-day varieties may not bulb fully.