Colorado
Planting zones in Routt County, Colorado
This county spans USDA zones 5a to 5b, so there is no single zone for Routt County and anyone who gives you one is rounding. 67% of its ZIP codes are zone 5a; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes Routt County, Colorado 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 Routt County is closing
Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives September 11 – September 20 across the 4 NOAA stations serving this county .
Your next season already has a date
The first job of it is 🧅 Green Onions, start indoors, around April 6 – April 19 — counted back from a last spring freeze of June 1 – June 14 here.
These are ranges across the whole county. The ZIP lookup above gives the dates from your own nearest station instead.
All 4 stations agreeAt least one station
Every one of the 4 NOAA stations serving this county counts June 14 – September 11 as growing season (89 days). Widening to any single station gives June 1 – September 20 (111 days).
That is a 22-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
Routt County covers 2 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 67% in zone 5a and wrong for the other 33%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 5a | 6 | 67% | |
| 5b | 3 | 33% |
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
Across the 4 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 89–109 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 76.8–83.3 °F in June–August. Summer rain over the same months runs 2.5–5.1" across those 4 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 33% 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 83 °F summer afternoon drying the soil faster than a cool one.
Every ZIP code in Routt 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 |
|---|---|---|---|
| 80428 | 5a | Steamboat Springs, CO | 40.4 km |
| 80463 | 5b | Yampa, CO | 23.3 km |
| 80467 | 5a | Yampa, CO | 9.2 km |
| 80469 | 5a | Yampa, CO | 8.1 km |
| 80479 | 5a | Yampa, CO | 19.0 km |
| 80483 | 5a | Yampa, CO | 7.5 km |
| 80487 | 5b | Steamboat Springs, CO | 11.6 km |
| 81639 | 5a | Hayden, CO | 8.1 km |
| 81653 | 5b | Baggs, WY | 38.3 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 Routt County
Every date below is anchored on the last spring freeze at each station and reported as a range across all 4 of them, because no one station speaks for the county.
| Crop | Job | When | Offset |
|---|---|---|---|
| 🧅 Green Onions | Start indoors | April 6 – April 19 | 8 wk before |
| 🌶️ Peppers | Start indoors | April 6 – April 19 | 8 wk before |
| 🥦 Broccoli | Start indoors | April 20 – May 3 | 6 wk before |
| 🥬 Cabbage | Start indoors | April 20 – May 3 | 6 wk before |
| 🥬 Collards | Start indoors | April 20 – May 3 | 6 wk before |
| 🥬 Kale | Start indoors | April 20 – May 3 | 6 wk before |
| 🥬 Leaf Lettuce | Start indoors | April 20 – May 3 | 6 wk before |
| 🫛 Peas | Direct sow | April 20 – May 3 | 6 wk before |
| 🥬 Spinach | Direct sow | April 20 – May 3 | 6 wk before |
| 🍠 Sweet Potato | Start indoors | April 20 – May 3 | 6 wk before |
| 🍅 Tomatoes | Start indoors | April 20 – May 3 | 6 wk before |
| 🥬 Bok Choy | Start indoors | April 27 – May 10 | 5 wk before |
| 🥬 Kohlrabi | Start indoors | April 27 – May 10 | 5 wk before |
| 🥬 Swiss Chard | Start indoors | April 27 – May 10 | 5 wk before |
| 🥬 Arugula | Direct sow | May 4 – May 17 | 4 wk before |
| 🥬 Baby Salad Greens | Direct sow | May 4 – May 17 | 4 wk before |
| 🥕 Beets | Direct sow | May 4 – May 17 | 4 wk before |
| 🧅 Green Onions | Direct sow | May 4 – May 17 | 4 wk before |
| 🥬 Mustard Greens | Direct sow | May 4 – May 17 | 4 wk before |
| 🌶️ Okra | Start indoors | May 4 – May 17 | 4 wk before |
| 🌱 Radishes | Direct sow | May 4 – May 17 | 4 wk before |
| 🥔 Turnips | Direct sow | May 4 – May 17 | 4 wk before |
| 🥬 Cabbage | Set out | May 11 – May 24 | 3 wk before |
| 🥕 Carrots | Direct sow | May 11 – May 24 | 3 wk before |
| 🥬 Collards | Direct sow | May 11 – May 24 | 3 wk before |
| 🥬 Collards | Set out | May 11 – May 24 | 3 wk before |
| 🥒 Cucumbers | Start indoors | May 11 – May 24 | 3 wk before |
| 🧅 Green Onions | Set out | May 11 – May 24 | 3 wk before |
| 🥬 Kale | Direct sow | May 11 – May 24 | 3 wk before |
| 🥬 Kale | Set out | May 11 – May 24 | 3 wk before |
| 🥬 Kohlrabi | Direct sow | May 11 – May 24 | 3 wk before |
| 🥬 Kohlrabi | Set out | May 11 – May 24 | 3 wk before |
| 🥬 Leaf Lettuce | Direct sow | May 11 – May 24 | 3 wk before |
| 🎃 Pumpkins | Start indoors | May 11 – May 24 | 3 wk before |
| 🎃 Summer Squash | Start indoors | May 11 – May 24 | 3 wk before |
| 🎃 Winter Squash | Start indoors | May 11 – May 24 | 3 wk before |
| 🥒 Zucchini | Start indoors | May 11 – May 24 | 3 wk before |
| 🥬 Bok Choy | Direct sow | May 18 – May 31 | 2 wk before |
| 🥬 Bok Choy | Set out | May 18 – May 31 | 2 wk before |
| 🥦 Broccoli | Set out | May 18 – May 31 | 2 wk before |
| 🌿 Cilantro | Direct sow | May 18 – May 31 | 2 wk before |
| 🥬 Leaf Lettuce | Set out | May 18 – May 31 | 2 wk before |
| 🥬 Swiss Chard | Direct sow | May 18 – May 31 | 2 wk before |
| 🥬 Swiss Chard | Set out | May 18 – May 31 | 2 wk before |
| 🌿 Dill | Direct sow | May 25 – June 7 | 1 wk before |
| 🫘 Bush Beans | Direct sow | June 8 – June 21 | 1 wk after |
| 🥒 Cucumbers | Set out | June 8 – June 21 | 1 wk after |
| 🎃 Pumpkins | Direct sow | June 8 – June 21 | 1 wk after |
| 🎃 Pumpkins | Set out | June 8 – June 21 | 1 wk after |
| 🎃 Summer Squash | Direct sow | June 8 – June 21 | 1 wk after |
| 🎃 Summer Squash | Set out | June 8 – June 21 | 1 wk after |
| 🌽 Sweet Corn | Direct sow | June 8 – June 21 | 1 wk after |
| 🍅 Tomatoes | Set out | June 8 – June 21 | 1 wk after |
| 🎃 Winter Squash | Direct sow | June 8 – June 21 | 1 wk after |
| 🎃 Winter Squash | Set out | June 8 – June 21 | 1 wk after |
| 🥒 Zucchini | Direct sow | June 8 – June 21 | 1 wk after |
| 🥒 Zucchini | Set out | June 8 – June 21 | 1 wk after |
| 🥒 Cucumbers | Direct sow | June 15 – June 28 | 2 wk after |
| 🌶️ Okra | Direct sow | June 15 – June 28 | 2 wk after |
| 🌶️ Okra | Set out | June 15 – June 28 | 2 wk after |
| 🌶️ Peppers | Set out | June 15 – June 28 | 2 wk after |
| 🫘 Southern Peas | Direct sow | June 15 – June 28 | 2 wk after |
| 🍠 Sweet Potato | Set out | June 15 – June 28 | 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 Routt County
Zone 5a carries 48 of 74 perennial edibles; zone 5a carries 48.
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 28 to be careful. Median June 1 – June 14 across 4 stations; May 15 is the optimistic end.
- First fall freeze
- Plan to August 29 to be careful. Median September 11 – September 20 across 4 stations; October 1 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 4 stations behind these numbers
All 4 NOAA stations whose normals this page quotes, spanning about 98 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 |
|---|---|---|---|---|
| Baggs, WY | USC00480484 | June 1 | September 18 | 108 days |
| Hayden, CO | USC00053867 | June 1 | September 20 | 109 days |
| Steamboat Springs, CO | USC00057936 | June 9 | September 12 | 93 days |
| Yampa, CO | USC00059265 | June 14 | September 11 | 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 county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.
Other places to compare
Routt County sits in Colorado. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.
More of Colorado
- Grand County, CO 5a–5b
- Logan County, CO 5b
- Montrose County, CO 6a–6b
- Lincoln County, CO 5b
- Montezuma County, CO 6a–7a
- Yuma County, CO 5b–6a
- Baca County, CO 6b
- Garfield County, CO 5b–6b
- Kit Carson County, CO 5b–6a
- Morgan County, CO 5a–5b
- Saguache County, CO 5a–5b
- Washington County, CO 5b
Counties with the same zones — 5a–5b
Matched on the exact zone set, not a dominant zone, so the winter answer on these pages really is the same one as here.
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 5a 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 5a, 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.