Frost Dates for Moses Lake, WA

In Moses Lake, WA, the average last spring frost is around Apr 27 and the average first fall frost around Oct 8, for a growing season of about 165 days. For frost-tender plants, wait until May 11, when the chance of frost drops to 10%.

Average last frostApr 2750% chance of frost after this date
Safe to plantMay 11only a 10% chance of frost after
Average first frostOct 850% chance of frost before this date
Growing season165 daysfrost-free in an average year

Based on NOAA 1991–2020 records from the Moses Lake Grant Co Airport, WA weather station, 6 miles away, elevation 1,196 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.

Frost probability by date

Chance of a 32°F frost after the spring date, or before the fall date.

ChanceLast spring frostFirst fall frost
10%May 11Sep 29
20%May 6Oct 1
30%May 2Oct 3
40%Apr 30Oct 5
50%Apr 27Oct 8
60%Apr 24Oct 11
70%Apr 21Oct 15
80%Apr 16Oct 18
90%Apr 10Oct 23

Light frost vs. hard freeze

Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.

TemperatureLast in springFirst in fall
Light frost (36°F)May 9Sep 29
Frost / freeze (32°F)Apr 27Oct 8
Hard freeze (28°F)Apr 10Oct 20

Planting calendar for Moses Lake

Start indoors Plant outside Fall planting
JanFebMarAprMayJunJulAugSepOctNovDec
Tomatoes
Indoors Mar 2 – Mar 16
Transplant May 4 – May 18
Peppers
Indoors Feb 16 – Mar 2
Transplant May 11 – May 25
Eggplant
Indoors Feb 16 – Mar 2
Transplant May 11 – May 25
Basil
Indoors Mar 16 – Mar 30
Transplant May 4 – May 18
Cucumbers
Indoors Mar 30 – Apr 6
Sow or transplant May 4 – May 18
Zucchini and summer squash
Indoors Mar 30 – Apr 6
Sow or transplant May 4 – May 18
Pumpkins and winter squash
Sow May 4 – May 18
Watermelons and melons
Indoors Mar 30 – Apr 6
Sow or transplant May 11 – May 25
Green beans
Sow May 4 – May 18
Sweet corn
Sow May 4 – May 18
Lettuce
Indoors Mar 16 – Mar 30
Sow or transplant Mar 30 – Apr 13
Fall sowing Aug 13 – Sep 10
Spinach
Sow Mar 16 – Apr 6
Fall sowing Aug 13 – Sep 3
Peas
Sow Mar 16 – Mar 30
Fall sowing Jul 30 – Aug 13
Kale
Indoors Mar 2 – Mar 16
Sow or transplant Mar 30 – Apr 13
Fall sowing Jul 30 – Aug 27
Broccoli
Indoors Mar 2 – Mar 16
Transplant Apr 13 – Apr 27
Fall sowing Jul 16 – Jul 30
Cabbage
Indoors Mar 2 – Mar 16
Transplant Apr 6 – Apr 20
Fall sowing Jul 16 – Jul 30
Carrots
Sow Apr 6 – Apr 27
Fall sowing Jul 16 – Jul 30
Radishes
Sow Mar 23 – Apr 13
Fall sowing Aug 27 – Sep 17
Beets
Sow Apr 6 – Apr 27
Fall sowing Jul 30 – Aug 13
Onions (sets or transplants)
Indoors Feb 2 – Feb 16
Plant Mar 30 – Apr 13
Potatoes
Plant Apr 6 – Apr 20
Garlic
Plant Oct 8 – Nov 5

Based on the average last frost (Apr 27) and first frost (Oct 8). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.

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