Planting zone for 04730 — Houlton, ME
ZIP code 04730 (Houlton, Aroostook County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 19 and the first fall frost September 23.
Where ZIP 04730 is
Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoomNot the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.
Was 4a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4b means →
Frost forecast — next 7 nights
live from the National Weather ServiceLoading the forecast for Houlton, ME…
Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.
Frost dates in Houlton, ME
A hard freeze (28 °F) usually ends around May 4 and returns around October 5.
From the NOAA station Houlton 5n, ME — within 1 mile, elevation 390 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.
When to plant vegetables in 04730
Counted from the median last spring frost (May 19) and first fall frost (Sep 23) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.
When spring arrived in 2026
In 2026, spring leaf-out near 04730 came on Apr 27 — 3 days earlier than the 1991–2020 average (Apr 30).
Apr 302026
Apr 27
The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).
Soil in Houlton, ME
The soil mapped at the center of ZIP 04730 is Colton — gravelly sandy loam, excessively drained.
Map unit: Colton gravelly sandy loam, 15 to 25 percent slopes.
Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 04730; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.
Climate in Houlton, ME
Average high and low, by month
Precipitation by month inches · ❄ = snowfall
NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Houlton 5n, ME (within 1 mile); precipitation: Houlton 5n, ME (within 1 mile). Daylight is calculated from latitude.
Nearby ZIP codes
2 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.
Questions about 04730
What planting zone is ZIP code 04730?
ZIP code 04730 (Houlton, ME) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).
When is the last frost in Houlton, ME?
The median last spring frost (32 °F) near 04730 is May 19; after June 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Houlton 5n station.
When is the first frost in Houlton, ME?
The median first fall frost near 04730 is September 23, giving a median frost-free growing season of 125 days.
When should I plant tomatoes in 04730?
Start tomato seeds indoors around Mar 24 – Apr 7 and set transplants outside around May 26 – Jun 9, one to three weeks after the median last frost.
How much rain and snow does 04730 get?
About 44.1 inches of precipitation a year and 96 inches of snowfall (NOAA 1991–2020 normals, Houlton 5n station).
How hot do summers get in Houlton, ME?
The average high peaks at 79 °F in July, with about 2 days a year at 90 °F or more.
What kind of soil does 04730 have?
The USDA soil survey maps Colton at the center of ZIP 04730: gravelly sandy loam, excessively drained, pH about 5.0 (strongly acidic).
Did spring come early in Houlton, ME in 2026?
Spring leaf-out near 04730 came on Apr 27 in 2026, 3 days earlier than the 1991–2020 average (Apr 30), according to the USA National Phenology Network Spring Index.
What kind of onions grow in Houlton, ME?
Long-day onions: the longest day near 04730 is 15 h 47 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).
Did the zone for 04730 change?
Yes. The 2012 USDA map put 04730 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.