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

Planting zone for 33920 — Alva, FL

ZIP code 33920 (Alva, Lee County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 33920 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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostrare
First frostrare
2012 zone9b

Was 9b 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 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Alva, FL…

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

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station La Belle, FL — 13 miles away, elevation 16 ft) the median growing season is 339 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 33920 came on Jan 12 — about the same time as the 1991–2020 average (Jan 14).

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 Alva, FL

The soil mapped at the center of ZIP 33920 is Malabar — fine sand, poorly drained.

TextureFine sanddrains and warms fast; dries out and needs more feeding
pH5.3strongly acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter3%moderate
Hydrologic groupA/Ddrains fast once dried out; wet otherwise
Farmland classFarmland of unique importanceUSDA classification

Map unit: Malabar fine sand, 0 to 2 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 33920; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alva, FL

Summer high92 °Faverage high, July
Winter low49 °Faverage low, January
Hot days135days a year at 90 °F or more
Freezing nights3nights a year at 32 °F or less
Growing degree days8,699base 50 °F — the season’s usable heat
Longest day13 h 49 mindaylight on June 21
Shortest day10 h 27 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation62.4 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°90°100°January: average high 75 °F, low 49 °F 75°49° JanFebruary: average high 79 °F, low 53 °F 79°53° FebMarch: average high 81 °F, low 55 °F 81°55° MarApril: average high 86 °F, low 60 °F 86°60° AprMay: average high 89 °F, low 65 °F 89°65° MayJune: average high 91 °F, low 71 °F 91°71° JunJuly: average high 92 °F, low 72 °F 92°72° JulAugust: average high 92 °F, low 73 °F 92°73° AugSeptember: average high 91 °F, low 72 °F 91°72° SepOctober: average high 87 °F, low 67 °F 87°67° OctNovember: average high 81 °F, low 59 °F 81°59° NovDecember: average high 77 °F, low 53 °F 77°53° Dec

Precipitation by month inches

0″2″4″6″8″10″12″January: 2.96 in precipitation 3.0 JanFebruary: 2.51 in precipitation 2.5 FebMarch: 1.88 in precipitation 1.9 MarApril: 1.94 in precipitation 1.9 AprMay: 3.63 in precipitation 3.6 MayJune: 11.30 in precipitation 11.3 JunJuly: 8.96 in precipitation 9.0 JulAugust: 10.13 in precipitation 10.1 AugSeptember: 11.05 in precipitation 11.1 SepOctober: 3.25 in precipitation 3.3 OctNovember: 2.40 in precipitation 2.4 NovDecember: 2.38 in precipitation 2.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: La Belle, FL (13 mi away); precipitation: Buckingham 1.7 Se, FL (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10a.

3397210a
Lehigh Acres, FL · 7 mi
3398210a
Punta Gorda, FL · 8 mi
3397110a
Lehigh Acres, FL · 8 mi
3390510a
Fort Myers, FL · 9 mi
3393610a
Lehigh Acres, FL · 10 mi
3397610a
Lehigh Acres, FL · 11 mi
3397310a
Lehigh Acres, FL · 11 mi
3397510a
Labelle, FL · 12 mi

Florida planting zones →

Questions about 33920

What planting zone is ZIP code 33920?

ZIP code 33920 (Alva, FL) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

How much rain and snow does 33920 get?

About 62.4 inches of precipitation a year (NOAA 1991–2020 normals, Buckingham 1.7 Se station).

How hot do summers get in Alva, FL?

The average high peaks at 92 °F in July, with about 135 days a year at 90 °F or more.

What kind of soil does 33920 have?

The USDA soil survey maps Malabar at the center of ZIP 33920: fine sand, poorly drained, pH about 5.3 (strongly acidic).

Did spring come early in Alva, FL in 2026?

Spring leaf-out near 33920 came on Jan 12 in 2026, about the same as the 1991–2020 average (Jan 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alva, FL?

Short-day onions: the longest day near 33920 is 13 h 49 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 33920 change?

Yes. The 2012 USDA map put 33920 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.