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

Planting zone for 93640 — Mendota, CA

ZIP code 93640 (Mendota, 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 93640 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 zone9b

Was 9b on the 2012 map — half a zone colder now. 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 Mendota, 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 Mendota, 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 — 27 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 93640

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 93640 came on Jan 31 — 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 Mendota, CA

The soil mapped at the center of ZIP 93640 is Ciervo — clay, moderately well drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH8.2alkaline; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter0.9%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Ciervo, wet-Ciervo complex, saline-sodic, 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 93640; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mendota, 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 (27 mi away); precipitation: Helm 2.7 Nne, CA (20 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.

936689a
Tranquillity, CA · 8 mi
936089b
Cantua Creek, CA · 13 mi
936229b
Firebaugh, CA · 13 mi
936609a
San Joaquin, CA · 16 mi
936309a
Kerman, CA · 18 mi
936279a
Helm, CA · 22 mi
936379a
Madera, CA · 22 mi
936659a
South Dos Palos, CA · 23 mi

California planting zones →

Questions about 93640

What planting zone is ZIP code 93640?

ZIP code 93640 (Mendota, 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 Mendota, CA?

The median last spring frost (32 °F) near 93640 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 Mendota, CA?

The median first fall frost near 93640 is November 26, giving a median frost-free growing season of 271 days.

When should I plant tomatoes in 93640?

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 93640 get?

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

How hot do summers get in Mendota, 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 93640 have?

The USDA soil survey maps Ciervo at the center of ZIP 93640: clay, moderately well drained, pH about 8.2 (alkaline).

Did spring come early in Mendota, CA in 2026?

Spring leaf-out near 93640 came on Jan 31 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 Mendota, CA?

Intermediate onions: the longest day near 93640 is 14 h 40 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 93640 change?

Yes. The 2012 USDA map put 93640 in zone 9b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.