What USDA hardiness zone is Mariposa County, California?

Mariposa County, California spans USDA hardiness zones 7a to 9b. 25% of its ZIP codes are zone 8b, so there is no single zone for the county.

When is the last spring frost in Mariposa County, California?

The median last spring freeze runs February 26 – May 24 across the 6 NOAA weather stations serving Mariposa County, California, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

California

Planting zones in Mariposa County, California

This county spans USDA zones 7a to 9b, so there is no single zone for Mariposa County and anyone who gives you one is rounding. 25% of its ZIP codes are zone 8b; the rest are not.

USDA zones 7a–9b 5 zones across 8 ZIP codes

ZIP codes 8 8 have a NOAA station within range

Weather stations 6 NOAA 1991–2020 normals, across 1,449 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Mariposa 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.

Mariposa County does not have one planting answer

Its own weather stations disagree about 11 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: 137 days
SO ENTRANCE YOSEMITE NP, CA US (USC00048380)
Longest season: 273 days
MERCED MUNI AP, CA US (USW00023257)

136 days of growing season separate those two stations, and both serve ZIP codes in Mariposa 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.

The whole dataset behind that →

All 6 stations agreeAt least one station

Every one of the 6 NOAA stations serving this county counts May 24 – October 10 as growing season (139 days). Widening to any single station gives February 26 – November 25 (272 days).

That is a 133-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

Mariposa County covers 5 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 25% in zone 8b and wrong for the other 75%. Here is the actual split.

Zone	ZIP codes	Share
8b	2	25%
9a	2	25%
9b	2	25%
7a	1	13%
8a	1	13%

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

Last spring freeze February 26 – May 24

First fall freeze October 10 – November 25

Across the 6 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 137–273 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 72.2–94 °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 0.1–1.1" across those 6 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 6% 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 88 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Mariposa 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
93623	8a	So Entrance Yosemite Np, CA	5.4 km
95306	9b	Merced Muni AP, CA	35.9 km
95311	8b	Groveland 2, CA	19.4 km
95318	8b	Yosemite Village 12 W, CA	10.4 km
95325	9b	Merced, CA	32.1 km
95338	9a	So Entrance Yosemite Np, CA	30.9 km
95345	9a	Yosemite Village 12 W, CA	22.5 km
95389	7a	Yosemite Park Hq, CA	14.7 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 Mariposa County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 6 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	January 1 – March 29	8 wk before
🌶️ Peppers	Start indoors	January 1 – March 29	8 wk before
🥦 Broccoli	Start indoors	January 15 – April 12	6 wk before
🥬 Cabbage	Start indoors	January 15 – April 12	6 wk before
🥬 Collards	Start indoors	January 15 – April 12	6 wk before
🥬 Kale	Start indoors	January 15 – April 12	6 wk before
🥬 Leaf Lettuce	Start indoors	January 15 – April 12	6 wk before
🫛 Peas	Direct sow	January 15 – April 12	6 wk before
🥬 Spinach	Direct sow	January 15 – April 12	6 wk before
🍠 Sweet Potato	Start indoors	January 15 – April 12	6 wk before
🍅 Tomatoes	Start indoors	January 15 – April 12	6 wk before
🥬 Bok Choy	Start indoors	January 22 – April 19	5 wk before
🥬 Kohlrabi	Start indoors	January 22 – April 19	5 wk before
🥬 Swiss Chard	Start indoors	January 22 – April 19	5 wk before
🥬 Arugula	Direct sow	January 29 – April 26	4 wk before
🥬 Baby Salad Greens	Direct sow	January 29 – April 26	4 wk before
🥕 Beets	Direct sow	January 29 – April 26	4 wk before
🧅 Green Onions	Direct sow	January 29 – April 26	4 wk before
🥬 Mustard Greens	Direct sow	January 29 – April 26	4 wk before
🌶️ Okra	Start indoors	January 29 – April 26	4 wk before
🌱 Radishes	Direct sow	January 29 – April 26	4 wk before
🥔 Turnips	Direct sow	January 29 – April 26	4 wk before
🥬 Cabbage	Set out	February 5 – May 3	3 wk before
🥕 Carrots	Direct sow	February 5 – May 3	3 wk before
🥬 Collards	Direct sow	February 5 – May 3	3 wk before
🥬 Collards	Set out	February 5 – May 3	3 wk before
🥒 Cucumbers	Start indoors	February 5 – May 3	3 wk before
🧅 Green Onions	Set out	February 5 – May 3	3 wk before
🥬 Kale	Direct sow	February 5 – May 3	3 wk before
🥬 Kale	Set out	February 5 – May 3	3 wk before
🥬 Kohlrabi	Direct sow	February 5 – May 3	3 wk before
🥬 Kohlrabi	Set out	February 5 – May 3	3 wk before
🥬 Leaf Lettuce	Direct sow	February 5 – May 3	3 wk before
🎃 Pumpkins	Start indoors	February 5 – May 3	3 wk before
🎃 Summer Squash	Start indoors	February 5 – May 3	3 wk before
🎃 Winter Squash	Start indoors	February 5 – May 3	3 wk before
🥒 Zucchini	Start indoors	February 5 – May 3	3 wk before
🥬 Bok Choy	Direct sow	February 12 – May 10	2 wk before
🥬 Bok Choy	Set out	February 12 – May 10	2 wk before
🥦 Broccoli	Set out	February 12 – May 10	2 wk before
🌿 Cilantro	Direct sow	February 12 – May 10	2 wk before
🥬 Leaf Lettuce	Set out	February 12 – May 10	2 wk before
🥬 Swiss Chard	Direct sow	February 12 – May 10	2 wk before
🥬 Swiss Chard	Set out	February 12 – May 10	2 wk before
🌿 Dill	Direct sow	February 19 – May 17	1 wk before
🫘 Bush Beans	Direct sow	March 5 – May 31	1 wk after
🥒 Cucumbers	Set out	March 5 – May 31	1 wk after
🎃 Pumpkins	Direct sow	March 5 – May 31	1 wk after
🎃 Pumpkins	Set out	March 5 – May 31	1 wk after
🎃 Summer Squash	Direct sow	March 5 – May 31	1 wk after
🎃 Summer Squash	Set out	March 5 – May 31	1 wk after
🌽 Sweet Corn	Direct sow	March 5 – May 31	1 wk after
🍅 Tomatoes	Set out	March 5 – May 31	1 wk after
🎃 Winter Squash	Direct sow	March 5 – May 31	1 wk after
🎃 Winter Squash	Set out	March 5 – May 31	1 wk after
🥒 Zucchini	Direct sow	March 5 – May 31	1 wk after
🥒 Zucchini	Set out	March 5 – May 31	1 wk after
🥒 Cucumbers	Direct sow	March 12 – June 7	2 wk after
🌶️ Okra	Direct sow	March 12 – June 7	2 wk after
🌶️ Okra	Set out	March 12 – June 7	2 wk after
🌶️ Peppers	Set out	March 12 – June 7	2 wk after
🫘 Southern Peas	Direct sow	March 12 – June 7	2 wk after
🍠 Sweet Potato	Set out	March 12 – June 7	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 Mariposa County

Zone 7a carries 58 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 June 11 to be careful. Median February 26 – May 24 across 6 stations; January 20 is the optimistic end.
First fall freeze: Plan to September 24 to be careful. Median October 10 – November 25 across 6 stations; December 16 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 6 stations behind these numbers

All 6 NOAA stations whose normals this page quotes, spanning about 62 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
Groveland 2, CA	USC00043669	April 22	November 2	192 days
Merced Muni AP, CA	USW00023257	February 26	November 25	273 days
Merced, CA	USC00045532	March 3	November 24	263 days
So Entrance Yosemite Np, CA	USC00048380	May 24	October 10	137 days
Yosemite Park Hq, CA	USC00049855	April 21	October 27	186 days
Yosemite Village 12 W, CA	USW00053150	May 12	November 1	171 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

Mariposa 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

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.

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.
MulchFor the perennials nearest their cold limit in zone 7a, where an insulated crown is what decides whether they come back.

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.