Island Park, Idaho, sits in USDA hardiness zone 3b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: zucchini, cranberry, cilantro, and okra. The site-level story — soil, sun, drainage — decides the rest.
Even in Island Park, 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 Island Park 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 Island Park — soil, climate, flood, and parcel records. How we handle your address.
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Island Park — the short answer
Island Park, Idaho: USDA zone 3b, about 91 days between hard freezes, across 4K acres of city.
- USDA zone
- 3b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jun 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~91
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 3b is Island Park's average, not your lot's — a low corner or a tree line moves it. Against Island Park's 91-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Island Park
Each reading below is measured for Island Park itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredIsland Park runs about 91 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredIsland Park sits in USDA hardiness zone 3b.
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 Island Park is in
Island Park sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Island Park's own centroid rather than borrowed from Fremont County.
What Grows in Island Park
Every plant below cleared Island Park's own zone 3b and its 91-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Island Park?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around May 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jun 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 4 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Island Park
Closest first, within ~10 miles of Island Park. Listing isn't leaking, and distance isn't exposure.
- ANTHONY SCARPELLIUnderground Storage Tanks · 0.9 mi
- Island Park KOAUnderground Storage Tanks · 0.9 mi
- STALEY SPRINGS LODGEUnderground Storage Tanks · 0.9 mi
- Lakeside LodgeUnderground Storage Tanks · 0.9 mi
- LAST CHANCE GENERAL STOREUnderground Storage Tanks · 0.9 mi
- Robin's RoostUnderground Storage Tanks · 1.1 mi
- 14N 43E 25BAB1Nitrate · 1.3 mi
- STAGE STOPUnderground Storage Tanks · 2.4 mi
- 14N 43E 02BCB1Nitrate · 2.6 mi
- 14N 43E 36CCC1Nitrate · 3.1 mi
- ELK CREEK SERVICEUnderground Storage Tanks · 5.7 mi
- 15N 43E 21AAD1Nitrate · 5.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Island Park'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 Island Park.
Total Sites
31
within ~10 miles of Island Park
Risk Level
Low
Highest-severity
20 nitrate monitoring sites
Severity Distribution
within ~10 miles of Island Park
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Island Park, Nitrate runs higher than the national average — 20 sites within ~10 miles of Island Park. That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Island Park
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 Island Park average
Your land is one point inside Island Park
Everything above resolves to Island Park as a whole — one PHZM band and one 28°F frost record, read across 4K acres. 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 Island Park Average
Island Park Average
- ●USDA Zones 3b, averaged across Island Park
- ●One soil character for all of Island Park
- ●Frost dates read at Island Park's scale: Jun 5 to Sep 4
YOUR Parcel
- ✓Your exact zone, not Island Park's 3b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Island Park
Pull a site-specific report for your exact address in Island Park, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Island Park averages can't show:
We read public map data around Island Park — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Island Park average
How we know this about Island Park
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 Island Park’s own record; 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 Island Park
When does frost risk typically end in Island Park?
The last hard freeze (28°F) in Island Park typically lands around Jun 5, 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 Jun 26.
When is the first frost in Island Park?
The first hard freeze (28°F) in Island Park typically arrives around Sep 4, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Aug 21, so the watching starts about Aug 5 — about 91 days after the spring freeze cleared.
How long is the growing season in Island Park?
Measured between 28°F hard freezes, Island Park sees about 91 frost-free days — roughly Jun 5 through Sep 4, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 26 to Aug 21, about 56 days.
Is the soil safe to grow vegetables in Island Park?
The federal record around Island Park is light — 31 documented sites across the 9 federal source types we checked, mostly Nitrate entries (20), the nearest Underground Storage Tanks record about 0.9 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 gardeners stretch the season in Island Park?
With about 91 frost-free days between hard freezes, Island Park rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 119 to 147 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the Jun 5 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Island Park's scale — its 3b band and its 91-day season. Your yard writes its own version of Island Park'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 Island Park’s own scale
6 of the readings below were taken at Island Park's own scale — its own ~91-day season between 28°F freezes, the 3,892 acres it covers and 31 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Island Park's own USDA hardiness band, zones 3bUSDA PHZM 2023
- Island Park's own 28°F hard-freeze dates, about Jun 5 and Sep 4 and the ~91-day span between themNOAA 1991–2020 Climate Normals
- 31 documented contamination sites on the federal record near Island Park, the closest Underground Storage Tanks record about 0.9 miles out from the town centreFederal environmental registers
- Island Park's boundary and the 3,892 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3b and a ~91-day seasonGrowable Ground crop-matching engine
- The ecoregion at Island Park's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Island Park's 3,892 acres read through its county's SSURGO summaryfrom Fremont County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Fremont County
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Fremont County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Island Park's 3,892 acreswhy one lot differs from the next →
- Which side of Island Park you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,892 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.9 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 Island Park-wide figureread your own land →