Alaska
Planting zones in Yukon-Koyukuk Census Area, Alaska
This census area spans USDA zones 1a to 3b, so there is no single zone for Yukon-Koyukuk Census Area and anyone who gives you one is rounding. 22% of its ZIP codes are zone 1b; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes Yukon-Koyukuk Census Area, Alaska 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.
The growing season in Yukon-Koyukuk Census Area is closing
Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives August 24 – September 17 across the 11 NOAA stations serving this census area .
Your next season already has a date
The first job of it is 🧅 Green Onions, start indoors, around March 18 – April 4 — counted back from a last spring freeze of May 13 – May 30 here.
These are ranges across the whole census area. The ZIP lookup above gives the dates from your own nearest station instead.
All 11 stations agreeAt least one station
Every one of the 11 NOAA stations serving this census area counts May 30 – August 24 as growing season (86 days). Widening to any single station gives May 13 – September 17 (127 days).
That is a 41-day difference inside one census area — 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
Yukon-Koyukuk Census Area covers 6 hardiness zones. A guide that gives the census area one zone has picked whichever is largest and rounded everyone else into it — fine for the 22% in zone 1b and wrong for the other 78%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 1b | 7 | 22% | |
| 2a | 7 | 22% | |
| 3a | 6 | 19% | |
| 1a | 5 | 16% | |
| 2b | 4 | 13% | |
| 3b | 3 | 9% |
Zones are published per ZIP code, so yours is exact even though the census area's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
Across the 11 NOAA stations serving this census area. 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 87–124 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 66.2–70.8 °F in June–August. Summer rain over the same months runs 6.1–8.7" across those 9 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 54% of it, so expect to make up the rest. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 67 °F summer afternoon drying the soil faster than a cool one.
Every ZIP code in Yukon-Koyukuk Census Area
Zones are published per ZIP code, not per census area, so this is the exact answer rather than the census area'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 |
|---|---|---|---|
| 99558 | 3b | none within range | — |
| 99590 | 3a | none within range | — |
| 99602 | 3a | none within range | — |
| 99627 | 2b | Mcgrath AP, AK | 83.7 km |
| 99665 | 3a | none within range | — |
| 99675 | 2a | Mcgrath AP, AK | 22.1 km |
| 99691 | 2b | Farewell Lake, AK | 20.9 km |
| 99701 | 3a | Bettles AP, AK | 92.3 km |
| 99720 | 1a | Bettles AP, AK | 67.8 km |
| 99722 | 1b | none within range | — |
| 99724 | 1a | none within range | — |
| 99726 | 1b | Bettles AP, AK | 18.3 km |
| 99730 | 3b | Central #2, AK | 40.1 km |
| 99733 | 1a | Central #2, AK | 36.0 km |
| 99740 | 3a | none within range | — |
| 99741 | 1b | Galena, AK | 0.1 km |
| 99745 | 1b | none within range | — |
| 99746 | 2a | none within range | — |
| 99748 | 2a | Kaltag AP, AK | 2.3 km |
| 99754 | 2a | Galena, AK | 42.6 km |
| 99756 | 1b | Tanana Calhoun Mem AP, AK | 67.4 km |
| 99757 | 2b | Minchumina, AK | 15.4 km |
| 99758 | 2a | Keystone Ridge, AK | 58.0 km |
| 99760 | 2a | Nenana Muni AP, AK | 15.2 km |
| 99765 | 2a | Kaltag AP, AK | 53.6 km |
| 99767 | 1b | Tanana Calhoun Mem AP, AK | 97.6 km |
| 99768 | 3a | Tanana Calhoun Mem AP, AK | 68.7 km |
| 99774 | 1a | none within range | — |
| 99777 | 1b | Tanana Calhoun Mem AP, AK | 2.6 km |
| 99781 | 2b | none within range | — |
| 99788 | 1a | none within range | — |
| 99790 | 3b | Mile 42 Steese, AK | 51.0 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 Yukon-Koyukuk Census Area
Every date below is anchored on the last spring freeze at each station and reported as a range across all 11 of them, because no one station speaks for the census area.
| Crop | Job | When | Offset |
|---|---|---|---|
| 🧅 Green Onions | Start indoors | March 18 – April 4 | 8 wk before |
| 🌶️ Peppers | Start indoors | March 18 – April 4 | 8 wk before |
| 🥦 Broccoli | Start indoors | April 1 – April 18 | 6 wk before |
| 🥬 Cabbage | Start indoors | April 1 – April 18 | 6 wk before |
| 🥬 Collards | Start indoors | April 1 – April 18 | 6 wk before |
| 🥬 Kale | Start indoors | April 1 – April 18 | 6 wk before |
| 🥬 Leaf Lettuce | Start indoors | April 1 – April 18 | 6 wk before |
| 🫛 Peas | Direct sow | April 1 – April 18 | 6 wk before |
| 🥬 Spinach | Direct sow | April 1 – April 18 | 6 wk before |
| 🍠 Sweet Potato | Start indoors | April 1 – April 18 | 6 wk before |
| 🍅 Tomatoes | Start indoors | April 1 – April 18 | 6 wk before |
| 🥬 Bok Choy | Start indoors | April 8 – April 25 | 5 wk before |
| 🥬 Kohlrabi | Start indoors | April 8 – April 25 | 5 wk before |
| 🥬 Swiss Chard | Start indoors | April 8 – April 25 | 5 wk before |
| 🥬 Arugula | Direct sow | April 15 – May 2 | 4 wk before |
| 🥬 Baby Salad Greens | Direct sow | April 15 – May 2 | 4 wk before |
| 🥕 Beets | Direct sow | April 15 – May 2 | 4 wk before |
| 🧅 Green Onions | Direct sow | April 15 – May 2 | 4 wk before |
| 🥬 Mustard Greens | Direct sow | April 15 – May 2 | 4 wk before |
| 🌶️ Okra | Start indoors | April 15 – May 2 | 4 wk before |
| 🌱 Radishes | Direct sow | April 15 – May 2 | 4 wk before |
| 🥔 Turnips | Direct sow | April 15 – May 2 | 4 wk before |
| 🥬 Cabbage | Set out | April 22 – May 9 | 3 wk before |
| 🥕 Carrots | Direct sow | April 22 – May 9 | 3 wk before |
| 🥬 Collards | Direct sow | April 22 – May 9 | 3 wk before |
| 🥬 Collards | Set out | April 22 – May 9 | 3 wk before |
| 🥒 Cucumbers | Start indoors | April 22 – May 9 | 3 wk before |
| 🧅 Green Onions | Set out | April 22 – May 9 | 3 wk before |
| 🥬 Kale | Direct sow | April 22 – May 9 | 3 wk before |
| 🥬 Kale | Set out | April 22 – May 9 | 3 wk before |
| 🥬 Kohlrabi | Direct sow | April 22 – May 9 | 3 wk before |
| 🥬 Kohlrabi | Set out | April 22 – May 9 | 3 wk before |
| 🥬 Leaf Lettuce | Direct sow | April 22 – May 9 | 3 wk before |
| 🎃 Pumpkins | Start indoors | April 22 – May 9 | 3 wk before |
| 🎃 Summer Squash | Start indoors | April 22 – May 9 | 3 wk before |
| 🎃 Winter Squash | Start indoors | April 22 – May 9 | 3 wk before |
| 🥒 Zucchini | Start indoors | April 22 – May 9 | 3 wk before |
| 🥬 Bok Choy | Direct sow | April 29 – May 16 | 2 wk before |
| 🥬 Bok Choy | Set out | April 29 – May 16 | 2 wk before |
| 🥦 Broccoli | Set out | April 29 – May 16 | 2 wk before |
| 🌿 Cilantro | Direct sow | April 29 – May 16 | 2 wk before |
| 🥬 Leaf Lettuce | Set out | April 29 – May 16 | 2 wk before |
| 🥬 Swiss Chard | Direct sow | April 29 – May 16 | 2 wk before |
| 🥬 Swiss Chard | Set out | April 29 – May 16 | 2 wk before |
| 🌿 Dill | Direct sow | May 6 – May 23 | 1 wk before |
| 🫘 Bush Beans | Direct sow | May 20 – June 6 | 1 wk after |
| 🥒 Cucumbers | Set out | May 20 – June 6 | 1 wk after |
| 🎃 Pumpkins | Direct sow | May 20 – June 6 | 1 wk after |
| 🎃 Pumpkins | Set out | May 20 – June 6 | 1 wk after |
| 🎃 Summer Squash | Direct sow | May 20 – June 6 | 1 wk after |
| 🎃 Summer Squash | Set out | May 20 – June 6 | 1 wk after |
| 🌽 Sweet Corn | Direct sow | May 20 – June 6 | 1 wk after |
| 🍅 Tomatoes | Set out | May 20 – June 6 | 1 wk after |
| 🎃 Winter Squash | Direct sow | May 20 – June 6 | 1 wk after |
| 🎃 Winter Squash | Set out | May 20 – June 6 | 1 wk after |
| 🥒 Zucchini | Direct sow | May 20 – June 6 | 1 wk after |
| 🥒 Zucchini | Set out | May 20 – June 6 | 1 wk after |
| 🥒 Cucumbers | Direct sow | May 27 – June 13 | 2 wk after |
| 🌶️ Okra | Direct sow | May 27 – June 13 | 2 wk after |
| 🌶️ Okra | Set out | May 27 – June 13 | 2 wk after |
| 🌶️ Peppers | Set out | May 27 – June 13 | 2 wk after |
| 🫘 Southern Peas | Direct sow | May 27 – June 13 | 2 wk after |
| 🍠 Sweet Potato | Set out | May 27 – June 13 | 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 Yukon-Koyukuk Census Area
Zone 3a carries 17 of 74 perennial edibles; zone 1a carries 0. 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 19 to be careful. Median May 13 – May 30 across 11 stations; May 3 is the optimistic end.
- First fall freeze
- Plan to August 9 to be careful. Median August 24 – September 17 across 11 stations; September 28 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 11 stations behind these numbers
All 11 NOAA stations whose normals this page quotes, spanning about 486 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 census area.
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 census area'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 |
|---|---|---|---|---|
| Bettles AP, AK | USW00026533 | May 22 | August 24 | 94 days |
| Central #2, AK | USC00501466 | May 25 | August 26 | 92 days |
| Farewell Lake, AK | USC00503009 | May 30 | September 5 | 97 days |
| Galena, AK | USC00503212 | May 18 | September 8 | 111 days |
| Kaltag AP, AK | USW00026502 | May 25 | September 3 | 101 days |
| Keystone Ridge, AK | USC00504621 | May 15 | September 16 | 122 days |
| Mcgrath AP, AK | USW00026510 | May 13 | September 13 | 120 days |
| Mile 42 Steese, AK | USC00505880 | May 28 | August 26 | 87 days |
| Minchumina, AK | USC00505881 | May 13 | September 17 | 124 days |
| Nenana Muni AP, AK | USW00026435 | May 15 | September 11 | 117 days |
| Tanana Calhoun Mem AP, AK | USW00026529 | May 29 | August 28 | 89 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 census area. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.
Other places to compare
Yukon-Koyukuk Census Area sits in Alaska. That page carries the whole state's zone spread, its metro areas, and every other census area in it with a page here.
More of Alaska
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.
- Trunk wrapZone 1a is cold enough that winter sun on a young trunk does more damage than the cold does.
- 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 1a, 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 census area: 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.