USDA Hardiness Zone 6b

Frost Dates for 99004 — Cheney, Washington

NOAA 1991–2020 normals from Spokane 17 SSW, WA (2,267 ft), 5 miles southeast.

Updated October 28, 2026

In Cheney, the last spring frost (32°F) is around May 30 in half of years and has passed by July 13 in nine years out of ten. The first fall frost comes around September 4, as early as August 21 one year in ten, leaving a typical freeze-free season of 94 days (NOAA, Spokane 17 SSW, WA).

Last spring frost: May 30
First fall frost: September 4
Growing season: 94 days
Hardiness zone: 6b

First snow: November 13
Last snow: April 4
Winters with snow: 100%
Snow per year: 45.4"

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Frost risk by date in Cheney

Half of springs at Spokane 17 SSW, WA see their last 32°F night by May 30; only one in ten is past it by May 9, and one in ten still has one after July 13. Planting tender crops after June 13 leaves a 30% risk of a frost on them, after June 23 20%, and after July 13 10%. The 44 days between the even-odds date and the one-in-ten date is the widest of the 113 Washington stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by September 4 in half of years, as early as August 21 one year in ten, and holds off past September 19 one year in ten. A hard freeze of 28°F follows 11 days later, around September 15; in spring the one-in-ten date for 28°F is May 22, 52 days before the 32°F one. The freeze-free season lasts 94 days in a typical year, the shortest of the 113 Washington stations; it reaches 120 days one year in ten and falls short of 56 one year in ten. On average 186 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between November 1 and March 2.

Spring: the chance of another night this cold after the date
Low	90%	80%	70%	60%	50%	40%	30%	20%	10%
36°F	too rare for a date
32°F	May 9	May 16	May 21	May 26	May 30	Jun 4	Jun 13	Jun 23	Jul 13
28°F	Apr 18	Apr 24	Apr 29	May 2	May 5	May 8	May 12	May 16	May 22
24°F	Mar 16	Mar 25	Mar 31	Apr 6	Apr 13	Apr 20	Apr 26	Apr 30	May 5
20°F	Feb 27	Mar 4	Mar 8	Mar 12	Mar 16	Mar 22	Mar 29	Apr 5	Apr 19
16°F	Feb 11	Feb 18	Feb 24	Feb 28	Mar 2	Mar 5	Mar 9	Mar 13	Mar 23

Fall: the chance the first night this cold has come by the date
Low	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	too rare for a date
32°F	Aug 21	Aug 26	Aug 30	Sep 1	Sep 4	Sep 6	Sep 9	Sep 13	Sep 19
28°F	Sep 2	Sep 6	Sep 9	Sep 12	Sep 15	Sep 18	Sep 22	Sep 26	Oct 3
24°F	Sep 12	Sep 18	Sep 22	Sep 27	Oct 1	Oct 3	Oct 7	Oct 14	Oct 22
20°F	Sep 28	Oct 3	Oct 6	Oct 12	Oct 17	Oct 22	Oct 28	Nov 2	Nov 10
16°F	Oct 10	Oct 18	Oct 22	Oct 28	Nov 1	Nov 5	Nov 12	Nov 22	Dec 1

Freeze probabilities 1991–2020 at Spokane 17 SSW, WA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 99004 →Compare Cheney with another place →

Frost risk through the year in Cheney

Frost curve for Cheney, Washington (Spokane 17 SSW, WA, NOAA 1991–2020): the chance of another 32°F night falls from 90% on May 9 to 50% on May 30 and 10% on July 13; the chance that the first fall one has come rises from 10% on August 21 to 50% on September 4 and 90% on September 19. — In Cheney, the spring curve drops under 10% on July 13 and the fall curve passes 10% on August 21, 39 days later; that gap is the shortest of the 113 Washington stations with frost dates. The spring risk falls from 90% to 10% over 65 days (May 9 to July 13) and the fall risk climbs from 10% to 90% over 29 days (August 21 to September 19): the last frost moves more from year to year than the first. At Spokane International Airport, WA, 11 miles north, the same gap runs from May 10 to September 29, 103 days longer.

Chance of a frost after each planting date in Cheney
Planted on	Another 32°F night	28°F night
May 16	80%	20%
May 23	66%	under 10%
May 3050% date	50%	under 10%
Jun 6	38%	under 10%
Jun 13	30%	under 10%
Jun 20	23%	under 10%

Weather by month in Cheney

July is the warmest month at Spokane 17 SSW, WA, averaging 84°F by day and 45°F at night; December is the coldest at 35°F and 21°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). No month is safe from a 32°F night: even the warmest has at least a 10% chance. In spring, June still brings one in 36% of years and July still brings one in 16% of years.

Warmth for growing adds up to 1,420 growing degree days a year (base 50°F), fewer than at 94% of the 113 Washington stations. 25% of them (357) have built up by the end of June, and July adds the most, 446. Precipitation totals 18.3 inches a year, most in December (2.6") and least in July (0.3"); May to September bring 23% of it.

Monthly normals 1991–2020 at Spokane 17 SSW, WA
Month	High °F	Low °F	Precip. in	32°F night	Nights ≤ 32°F	GDD 50°F
Jan	36	22	2.2	100%	27	0
Feb	40	22	1.7	100%	25	0
Mar	49	27	2.1	100%	24	1
Apr	57	32	1.5	100%	18	18
May	67	38	1.7	94%	8	115
Jun	73	42	1.3	36%	1	224
Jul	84	45	0.3	16%	<1	446
Aug	84	43	0.4	34%	1	418
Sep	74	35	0.5	98%	11	170
Oct	59	29	1.6	100%	20	28
Nov	43	25	2.4	100%	23	1
Dec	35	21	2.6	100%	28	0

Monthly normals 1991–2020 at Spokane 17 SSW, WA (2,267 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Spokane International Airport, WA, 11 miles north of Cheney, has a last frost 34 days earlier (April 26), a first frost 38 days later (October 12), a season 74 days longer.

Frost dates for 99224 (Spokane) →

When it snows in Cheney, Washington

The first measurable snow (0.1 inch or more) in Cheney usually arrives around November 13, and the last of the season around April 4. Those are the middle dates across the winters of 1991–2020 at Spokane International Airport, WA, 11.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 56 days after the last snow.

Planting calendar for 99004

What to do and when, from the 50% frost dates for Cheney, Washington
When	What to do
March 21 – April 4	Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
April 4 – April 18	Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
May 2 – May 16	Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 30 onward	Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by June 12	Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by August 21	Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
September 4 onward	Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 99004 is 5 miles from Spokane 17 SSW, WA, which stands at 2,267 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 99004 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Washington →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.