Roche Harbor, Washington, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
These conditions suit artichoke, fig, california poppy, and cabbage — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Roche Harbor, 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 Roche Harbor 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 Roche Harbor — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Roche Harbor — the short answer
Roche Harbor, Washington: USDA zone 9a, about 300 days between hard freezes, across 3K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 9
- San Juan County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 6
- San Juan County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~300
- San Juan County normal — NOAA 1991–2020, nearest to this town
- Town 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 San Juan County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Roche Harbor's average, not your lot's — a low corner or a tree line moves it. Against Roche Harbor's 300-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Roche Harbor
Each reading below is measured for Roche Harbor itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsRoche Harbor runs about 300 days between hard freezes (read from San Juan County, the closest normal to Roche Harbor) — 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
MeasuredRoche Harbor sits in USDA hardiness zone 9a.
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 Roche Harbor is in
Roche Harbor sits in the Puget Lowland — EPA Level III, inside the wider Marine West Coast Forest. That is read at Roche Harbor's own centroid rather than borrowed from San Juan County.
What Grows in Roche Harbor
Every plant below cleared Roche Harbor's own zone 9a and its 300-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Roche Harbor?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Jan 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 6 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
What's on the federal record near Roche Harbor
Closest first, within ~10 miles of Roche Harbor. Listing isn't leaking, and distance isn't exposure.
- 36N/03W-17E01Nitrate · 0.7 mi
- ROCHE HARBOR RESORTUnderground Storage Tanks · 1.2 mi
- 35N/04W-25E01Nitrate · 1.5 mi
- 36N/04W-25E02Nitrate · 1.6 mi
- BURGET PROPERTYUnderground Storage Tanks · 2.9 mi
- SNUG HARBOR RESORTUnderground Storage Tanks · 3.2 mi
- W A ROULEAU & SON INCUnderground Storage Tanks · 3.8 mi
- FRIDAY HARBOR TOWN OFPFAS · 4.2 mi
- PETRO SAN JUANUnderground Storage Tanks · 5.4 mi
- FEDEX GROUND SAN JEAN ISLANDSBrownfields · 6.2 mi
- DEER HARBOR RESORT & MARINAUnderground Storage Tanks · 6.5 mi
- ORCAS POWER AND LIGHT COMPANYUnderground Storage Tanks · 6.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Roche Harbor'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 Roche Harbor.
Sources Checked
within ~10 miles of Roche Harbor
Severity Distribution
within ~10 miles of Roche Harbor
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Roche Harbor, Underground Storage Tanks runs higher than the national average — 26 sites within ~10 miles of Roche Harbor. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Roche Harbor
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 Roche Harbor average
Your land is one point inside Roche Harbor
Everything above resolves to Roche Harbor as a whole — one PHZM band, read across 3K acres, with hard-freeze dates borrowed from San Juan County’s record because no 30-year normal resolves at this town’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 town 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 Roche Harbor Average
Roche Harbor Average
- ●USDA Zones 9a, averaged across Roche Harbor
- ●One soil character for all of Roche Harbor
- ●Frost dates read at Roche Harbor's scale: Feb 9 to Dec 6
YOUR Parcel
- ✓Your exact zone, not Roche Harbor's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Roche Harbor
Pull a site-specific report for your exact address in Roche Harbor, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Roche Harbor averages can't show:
We read public map data around Roche Harbor — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Roche Harbor average
How we know this about Roche Harbor
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at San Juan 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 town grain anywhere on this page — there is no town-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 Roche Harbor
When does frost risk typically end in Roche Harbor?
The last hard freeze (28°F) in Roche Harbor typically lands around Feb 9, 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 Mar 2.
When is the first frost in Roche Harbor?
The first hard freeze (28°F) in Roche Harbor typically arrives around Dec 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 22, so the watching starts about Nov 6 — about 300 days after the spring freeze cleared.
How long is the growing season in Roche Harbor?
Measured between 28°F hard freezes, Roche Harbor sees about 300 frost-free days — roughly Feb 9 through Dec 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 2 to Nov 22, about 265 days.
Is the soil safe to grow vegetables in Roche Harbor?
The federal record around Roche Harbor is light — 39 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (26), the nearest Nitrate record about 0.7 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Roche Harbor?
From about Nov 6 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 6 (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 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Roche Harbor's scale — its 9a band and its 300-day season. Your yard writes its own version of Roche Harbor'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 Roche Harbor’s own scale
5 of the readings below were taken at Roche Harbor's own scale — the 2,570 acres it covers and 39 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Roche Harbor's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 39 documented contamination sites on the federal record near Roche Harbor, the closest Nitrate record about 0.7 miles out from the town centreFederal environmental registers
- Roche Harbor's boundary and the 2,570 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~300-day seasonGrowable Ground crop-matching engine
- The ecoregion at Roche Harbor's own centroid, the Puget LowlandUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Roche Harbor has no normal of its own, so its county's is the closest measured readfrom San Juan County
- Soil character — no town-scale survey exists, so Roche Harbor's 2,570 acres read through its county's SSURGO summaryfrom San Juan County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom San Juan County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom San Juan County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Roche Harbor's 2,570 acreswhy one lot differs from the next →
- Which side of Roche Harbor you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,570 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.7 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 Roche Harbor-wide figureread your own land →