Planting zone for 94576 — Deer Park, CA
ZIP code 94576 (Deer Park, Napa County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is April 7 and the first fall frost December 5.
Where ZIP 94576 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 9a 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 9b means →
Frost forecast — next 7 nights
live from the National Weather ServiceLoading the forecast for Deer Park, CA…
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 Deer Park, CA
A hard freeze (28 °F) usually ends around February 18 and returns around December 30.
From the NOAA station Angwin Pacific Union College, CA — 2 miles away, elevation 1,716 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 94576
Counted from the median last spring frost (Apr 7) and first fall frost (Dec 5) 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 94576 came on Jan 27 — 4 days earlier than the 1991–2020 average (Jan 31).
Jan 312026
Jan 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 Deer Park, CA
The soil mapped at the center of ZIP 94576 is Boomer — slightly decomposed plant material, well drained.
Map unit: Boomer loam, volcanic bedrock, 2 to 35 percent slopes, MLRA 15.
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 94576; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.
Climate in Deer Park, CA
Average high and low, by month
Precipitation by month inches
NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Angwin Pacific Union College, CA (2 mi away); precipitation: Angwin Pacific Union College, CA (2 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 94576
What planting zone is ZIP code 94576?
ZIP code 94576 (Deer Park, CA) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).
When is the last frost in Deer Park, CA?
The median last spring frost (32 °F) near 94576 is April 7; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Angwin Pacific Union College station.
When is the first frost in Deer Park, CA?
The median first fall frost near 94576 is December 5, giving a median frost-free growing season of 245 days.
When should I plant tomatoes in 94576?
Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.
How much rain and snow does 94576 get?
About 39.7 inches of precipitation a year (NOAA 1991–2020 normals, Angwin Pacific Union College station).
How hot do summers get in Deer Park, CA?
The average high peaks at 85 °F in July, with about 27 days a year at 90 °F or more.
What kind of soil does 94576 have?
The USDA soil survey maps Boomer at the center of ZIP 94576: slightly decomposed plant material, well drained, pH about 5.5 (moderately acidic).
Did spring come early in Deer Park, CA in 2026?
Spring leaf-out near 94576 came on Jan 27 in 2026, 4 days earlier than the 1991–2020 average (Jan 31), according to the USA National Phenology Network Spring Index.
What kind of onions grow in Deer Park, CA?
Intermediate onions: the longest day near 94576 is 14 h 52 min, so day-neutral types bulb best; long-day varieties may not bulb fully.
Did the zone for 94576 change?
Yes. The 2012 USDA map put 94576 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.