Planting zone for 18656 — Sweet Valley, PA
ZIP code 18656 (Sweet Valley, Luzerne County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 4 and the first fall frost October 11.
Where ZIP 18656 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.
Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6a means →
Frost forecast — next 7 nights
live from the National Weather ServiceLoading the forecast for Sweet Valley, PA…
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 Sweet Valley, PA
A hard freeze (28 °F) usually ends around April 22 and returns around October 24.
From the NOAA station Benton 3 Ne, PA — 11 miles away, elevation 1,096 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 18656
Counted from the median last spring frost (May 4) and first fall frost (Oct 11) 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 18656 came on Apr 8 — 5 days earlier than the 1991–2020 average (Apr 13).
Apr 132026
Apr 8
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 Sweet Valley, PA
The soil mapped at the center of ZIP 18656 is Oquaga — moderately decomposed plant material, well drained.
Map unit: Oquaga and Lordstown channery silt loams, steep, rubbly.
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 18656; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.
Climate in Sweet Valley, PA
Average high and low, by month
Precipitation by month inches · ❄ = snowfall
NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Benton 3 Ne, PA (11 mi away); precipitation: Shickshinny 3 N, PA (11 mi away). Daylight is calculated from latitude.
Nearby ZIP codes
1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.
Questions about 18656
What planting zone is ZIP code 18656?
ZIP code 18656 (Sweet Valley, PA) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).
When is the last frost in Sweet Valley, PA?
The median last spring frost (32 °F) near 18656 is May 4; after May 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Benton 3 Ne station.
When is the first frost in Sweet Valley, PA?
The median first fall frost near 18656 is October 11, giving a median frost-free growing season of 159 days.
When should I plant tomatoes in 18656?
Start tomato seeds indoors around Mar 9 – Mar 23 and set transplants outside around May 11 – May 25, one to three weeks after the median last frost.
How much rain and snow does 18656 get?
About 47.5 inches of precipitation a year and 36 inches of snowfall (NOAA 1991–2020 normals, Shickshinny 3 N station).
How hot do summers get in Sweet Valley, PA?
The average high peaks at 80 °F in July, with about 4 days a year at 90 °F or more.
What kind of soil does 18656 have?
The USDA soil survey maps Oquaga at the center of ZIP 18656: moderately decomposed plant material, well drained, pH about 4.8 (strongly acidic).
Did spring come early in Sweet Valley, PA in 2026?
Spring leaf-out near 18656 came on Apr 8 in 2026, 5 days earlier than the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.
What kind of onions grow in Sweet Valley, PA?
Long-day onions: the longest day near 18656 is 15 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).