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When to plant in Boulder City, NV

USDA Zone 9a

Everything below — frost dates, hardiness zone, and what to plant when in Boulder City, Nevada — is derived from the closest NOAA station with complete climate normals.

With about 330 frost-free days, Boulder City supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. These dates come from a station roughly 21 km away, the closest with full normals; terrain around Boulder City (elevation, water, pavement) can move your real frost dates a few days either way. In zone 9a, frost is a minor factor for Boulder City — most perennials thrive, and annual vegetables can go out early and stay late.

Station · ALAN BIBLE VISITOR CTR · 21.2 km
Last spring frost
January 21
50% chance · 32°F
First fall frost
December 17
50% chance · 32°F
Growing season
330 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for Boulder CityA year-band showing 32°F frost risk from January to December for Boulder City: last spring frost around January 21, first fall frost around December 17, about 330 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

Frost probability

ALAN BIBLE VISITOR CTR · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Boulder City’s own odds, recorded at ALAN BIBLE VISITOR CTR.

Frost-probability curves for Boulder CityProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 21 and the first fall frost around December 17, giving about 330 frost-free days.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FMar 13Feb 13Jan 18Nov 23Dec 5Dec 18
32°FMar 5Jan 21Dec 29Dec 2Dec 17Jan 3
28°FMar 3Jan 10Dec 19Dec 8Dec 30Feb 3

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19

Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.

Add the next planting windows to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Boulder City, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 33 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

ALAN BIBLE VISITOR CTR
Primary
21 km · 500 m elevation
SPRING
Jan 21
FALL
Dec 17
WILLOW BEACH
23 km · 226 m elevation
SPRING
Jan 7
FALL
Dec 29
LAS VEGAS WFO
33 km · 693 m elevation
SPRING
Feb 4
FALL
Dec 5

Boulder City planting FAQ

When is the last spring frost in Boulder City, NV?

Boulder City's average last spring frost falls near January 21 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.

When is the first fall frost in Boulder City, NV?

Expect Boulder City's first fall frost near December 17 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.

What hardiness zone is Boulder City in?

Boulder City is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.

How long is the growing season in Boulder City?

Boulder City has about 330 frost-free days — a long growing season — between the average last spring frost (January 21) and first fall frost (December 17).

When should I plant tomatoes in Boulder City?

For Boulder City, sow tomatoes indoors about November 26–December 10 and move the seedlings out around January 28, after the last spring frost.

Planting reminders

Never miss a window in Boulder City

An email when it’s time to start seeds, transplant, and sow — timed to Boulder City’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at ALAN BIBLE VISITOR CTR, 21 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Boulder City, NV — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00260125. Retrieved from https://blissgarden.com/nevada/boulder-city.
When to Plant in Boulder City, NV — Frost Dates & Zone 9a — BlissGarden