Suisun City, California, sits in USDA hardiness zone 9b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include okra, meyer lemon, california poppy, and artichoke; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Suisun City, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Suisun City lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Suisun City — soil, climate, flood, and parcel records. How we handle your address.
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Suisun City — the short answer
Suisun City, California: USDA zone 9b, about 335 days between hard freezes, across 3K acres of city.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 15
- Solano County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 16
- Solano County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~335
- Solano County normal — NOAA 1991–2020, nearest to this town
- City area
- 3K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Solano County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Suisun City's average, not your lot's — a low corner or a tree line moves it. Against Suisun City's 335-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Suisun City
Each reading below is measured for Suisun City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSuisun City runs about 335 days between hard freezes (read from Solano County, the closest normal to Suisun City) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSuisun City sits in USDA hardiness zone 9b.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Suisun City is in
Suisun City sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Suisun City's own centroid, and it is not what its county reads: Solano County is mostly Central California Valley. The wider page above you is answering a different question about different ground.
What Grows in Suisun City
Every plant below cleared Suisun City's own zone 9b and its 335-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Suisun City?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 16 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
What's on the federal record near Suisun City
Closest first, within ~10 miles of Suisun City. Listing isn't leaking, and distance isn't exposure.
- CITY OF SUISUN FIRESTATIONBrownfields · 650 ft
- BLANCA MUNOZBrownfields · 1400 ft
- KRISTEN ABERSONBrownfields · 2500 ft
- Suisun Union 76Underground Storage Tanks · 2500 ft
- GAWFCO ENTERPRISES INC DBA SUISUN VALEROBrownfields · 2500 ft
- Ishaq Trading Corporation Sunset ChevronUnderground Storage Tanks · 0.5 mi
- SUNSET CHEVRONBrownfields · 0.5 mi
- 7-ELEVEN INC #32180Underground Storage Tanks · 0.5 mi
- 7 ELEVEN INC #32180Brownfields · 0.5 mi
- Lawler ChevronUnderground Storage Tanks · 0.6 mi
- ASHRIA LLCBrownfields · 0.6 mi
- RALEYS 380Brownfields · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Suisun City's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Suisun City.
Sources Checked
within ~10 miles of Suisun City
Severity Distribution
within ~10 miles of Suisun City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Suisun City, Brownfields runs higher than the national average — 862 sites within ~10 miles of Suisun City. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Suisun City
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Suisun City average
Your land is one point inside Suisun City
Everything above resolves to Suisun City as a whole — one PHZM band, read across 3K acres, with hard-freeze dates borrowed from Solano County’s record because no 30-year normal resolves at this city’s own centroid. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Suisun City Average
Suisun City Average
- ●USDA Zones 9b, averaged across Suisun City
- ●One soil character for all of Suisun City
- ●Frost dates read at Suisun City's scale: Jan 15 to Dec 16
YOUR Parcel
- ✓Your exact zone, not Suisun City's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Suisun City
Pull a site-specific report for your exact address in Suisun City, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Suisun City averages can't show:
We read public map data around Suisun City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Suisun City average
How we know this about Suisun City
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Solano County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Suisun City
When does frost risk typically end in Suisun City?
The last hard freeze (28°F) in Suisun City typically lands around Jan 15, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Feb 5.
When is the first frost in Suisun City?
The first hard freeze (28°F) in Suisun City typically arrives around Dec 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 2, so the watching starts about Nov 16 — about 335 days after the spring freeze cleared.
How long is the growing season in Suisun City?
Measured between 28°F hard freezes, Suisun City sees about 335 frost-free days — roughly Jan 15 through Dec 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 5 to Dec 2, about 300 days.
Is the soil safe to grow vegetables in Suisun City?
The federal record around Suisun City is a meaningful one — 996 documented sites, mostly Brownfields entries (862), the nearest Brownfields record about 0.1 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Suisun City?
From about Nov 16 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 16 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Suisun City's scale — its 9b band and its 335-day season. Your yard writes its own version of Suisun City's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Suisun City’s own scale
5 of the readings below were taken at Suisun City's own scale — the 2,563 acres it covers and 996 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Suisun City's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 996 documented contamination sites on the federal record near Suisun City, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Suisun City's boundary and the 2,563 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~335-day seasonGrowable Ground crop-matching engine
- Suisun City sits in the Central California Foothills and Coastal Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Suisun City has no normal of its own, so its county's is the closest measured readfrom Solano County
- Soil character — no town-scale survey exists, so Suisun City's 2,563 acres read through its county's SSURGO summaryfrom Solano County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Solano County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Solano County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Suisun City's 2,563 acreswhy one lot differs from the next →
- Which side of Suisun City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,563 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.1 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Suisun City-wide figureread your own land →
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