Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 20680 — Ridge, MD

ZIP code 20680 (Ridge, St. Mary's County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is March 30 and the first fall frost November 14.

Where ZIP 20680 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not 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.

Zone8a10 to 15 °F
Coldest night−12.2 to −9.4 °C
Last frostMar 30
First frostNov 14
2012 zone7b

Was 7b 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 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ridge, MD…

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 Ridge, MD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 30median — 50% chance of a later frost
Safe for tender plantsApril 11only 10% chance of frost after
First fall frostNovember 14median — 10% chance by Oct 29
Growing season229 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 19 and returns around November 29.

From the NOAA station St Inigoes Webster Nolf, MD — 3 miles away, elevation 20 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 20680

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 16 – Mar 2
SpinachSow outdoors · Feb 16 – Mar 9
Broccoli, cabbageStart indoors · Jan 19 – Feb 2
Broccoli, cabbageTransplant · Mar 9 – Mar 23
Onion setsPlant outdoors · Mar 2 – Mar 16
PotatoesPlant outdoors · Mar 9 – Mar 23
LettuceSow outdoors · Mar 2 – Mar 16
Carrots, beetsSow outdoors · Mar 9 – Mar 23
TomatoesStart indoors · Feb 2 – Feb 16
TomatoesTransplant · Apr 6 – Apr 20
Peppers, eggplantStart indoors · Jan 19 – Feb 2
Peppers, eggplantTransplant · Apr 13 – Apr 27
BeansSow outdoors · Apr 6 – Apr 20
Sweet cornSow outdoors · Apr 6 – Apr 20
Cucumbers, squashSow outdoors · Apr 6 – Apr 20
Fall lettuce, spinachSow outdoors · Sep 19 – Oct 3
GarlicPlant cloves · Oct 31 – Dec 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 30) and first fall frost (Nov 14) 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 20680 came on Mar 9 — 5 days later than the 1991–2020 average (Mar 4).

JanFebMarAprMayJun

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 Ridge, MD

The soil mapped at the center of ZIP 20680 is Mattapex — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter1.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Mattapex silt loam, 2 to 5 percent slopes, Northern Coastal Plain.

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 20680; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ridge, MD

Summer high87 °Faverage high, July
Winter low30 °Faverage low, January
Hot days29days a year at 90 °F or more
Freezing nights69nights a year at 32 °F or less
Growing degree days4,397base 50 °F — the season’s usable heat
Longest day14 h 49 mindaylight on June 21
Shortest day9 h 31 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation50.6 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 46 °F, low 30 °F 46°30° JanFebruary: average high 48 °F, low 31 °F 48°31° FebMarch: average high 56 °F, low 37 °F 56°37° MarApril: average high 67 °F, low 47 °F 67°47° AprMay: average high 75 °F, low 57 °F 75°57° MayJune: average high 85 °F, low 66 °F 85°66° JunJuly: average high 87 °F, low 71 °F 87°71° JulAugust: average high 85 °F, low 68 °F 85°68° AugSeptember: average high 79 °F, low 62 °F 79°62° SepOctober: average high 69 °F, low 51 °F 69°51° OctNovember: average high 59 °F, low 41 °F 59°41° NovDecember: average high 50 °F, low 33 °F 50°33° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.45 in precipitation 3.5 JanFebruary: 2.81 in precipitation 2.8 FebMarch: 3.77 in precipitation 3.8 MarApril: 3.88 in precipitation 3.9 AprMay: 4.55 in precipitation 4.5 MayJune: 4.41 in precipitation 4.4 JunJuly: 4.35 in precipitation 4.3 JulAugust: 5.65 in precipitation 5.7 AugSeptember: 5.16 in precipitation 5.2 SepOctober: 5.28 in precipitation 5.3 OctNovember: 3.39 in precipitation 3.4 NovDecember: 3.89 in precipitation 3.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: St Inigoes Webster Nolf, MD (3 mi away); precipitation: Ridge 1.0 N, MD (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8a.

206848a
Saint Inigoes, MD · 2 mi
206288a
Dameron, MD · 4 mi
206878a
Scotland, MD · 4 mi
206308a
Drayden, MD · 5 mi
206868a
Saint Marys City, MD · 6 mi
206928a
Valley Lee, MD · 8 mi
206678a
Park Hall, MD · 8 mi
206748a
Piney Point, MD · 9 mi

Maryland planting zones →

Questions about 20680

What planting zone is ZIP code 20680?

ZIP code 20680 (Ridge, MD) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Ridge, MD?

The median last spring frost (32 °F) near 20680 is March 30; after April 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, St Inigoes Webster Nolf station.

When is the first frost in Ridge, MD?

The median first fall frost near 20680 is November 14, giving a median frost-free growing season of 229 days.

When should I plant tomatoes in 20680?

Start tomato seeds indoors around Feb 2 – Feb 16 and set transplants outside around Apr 6 – Apr 20, one to three weeks after the median last frost.

How much rain and snow does 20680 get?

About 50.6 inches of precipitation a year (NOAA 1991–2020 normals, Ridge 1.0 N station).

How hot do summers get in Ridge, MD?

The average high peaks at 87 °F in July, with about 29 days a year at 90 °F or more.

What kind of soil does 20680 have?

The USDA soil survey maps Mattapex at the center of ZIP 20680: silt loam, moderately well drained, pH about 6.0 (slightly acidic).

Did spring come early in Ridge, MD in 2026?

Spring leaf-out near 20680 came on Mar 9 in 2026, 5 days later than the 1991–2020 average (Mar 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ridge, MD?

Intermediate onions: the longest day near 20680 is 14 h 49 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 20680 change?

Yes. The 2012 USDA map put 20680 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.