Frost Dates & Planting Calendar for Evanston, WY

The average first fall frost in Evanston, WY is September 12, and the average last spring frost is June 12, giving a growing season of about 90 days.

Plan your garden around Evanston, WY's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.

Last Spring Frost

June 12

Safe Jul 2 Typical Jun 12 Risky May 26

First Fall Frost

September 12

Safe Aug 26 Typical Sep 12 Risky Sep 25

Growing Season

90 days

Typical last frost to typical first frost.

USDA Hardiness Zone

Zone 5a

A classic four-season climate with cold winters and a solid summer growing season.

Data: NOAA station EVANSTON 1 E, WY US, 1.1 km away.

— days until the typical last spring frost

How Evanston Compares

Evanston's typical last spring frost (Jun 12) comes later than in 95% of the 19 Wyoming cities we track.
Its 90-day growing season is 46 days shorter than the Wyoming median of 136 days.
July is the warmest month (average high 81°F) and January the coldest (average low 11°F).

Monthly Temperatures

Avg. high Avg. temp Avg. low

Planting Calendar

Vegetables
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Tomato	Apr 17 – May 1	—	Jun 19 – Jun 26	—	60–85 days	Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed.
Pepper	Apr 3 – Apr 17	—	Jun 19 – Jul 3	—	60–90 days	Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost.
Eggplant	Apr 3 – Apr 17	—	Jun 26 – Jul 3	—	65–85 days	Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant.
Cucumber	May 15 – May 22	Jun 19 – Jun 26	Jun 19 – Jun 26	—	50–65 days	Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm.
Zucchini	May 22 – May 29	Jun 19 – Jul 3	Jun 19 – Jun 26	—	45–55 days	Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start.
Winter Squash	May 15 – May 22	Jun 19 – Jul 3	Jun 19 – Jun 26	—	80–110 days	Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates.
Pumpkin	—	Jun 19 – Jul 3	—	—	90–120 days	Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it.
Watermelon	May 15 – May 22	—	Jun 26 – Jul 3	—	70–90 days	Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.
Cantaloupe	May 15 – May 22	—	Jun 26 – Jul 3	—	70–90 days	Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting.
Corn	—	Jun 12 – Jun 26	—	—	60–100 days	Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks.
Green Bean	—	Jun 12 – Jun 26	—	—	50–65 days	Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush.
Pea	—	May 1 – May 15	—	—	55–70 days	Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Lettuce	—	May 15 – May 29	—	Jul 18 – Aug 1	45–60 days	Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts.
Spinach	—	May 1 – May 15	—	Jul 18 – Aug 1	40–50 days	Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Kale	—	May 15 – May 29	—	Jul 4 – Jul 18	50–65 days	Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants.
Arugula	—	May 15 – May 29	—	Aug 1 – Aug 8	30–40 days	Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks.
Swiss Chard	—	May 22 – Jun 5	—	—	50–60 days	Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too.
Broccoli	Apr 24 – May 8	—	May 22 – May 29	Jul 11 – Jul 18	55–80 days	Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost).
Cauliflower	Apr 24 – May 8	—	May 29 – Jun 5	Jul 4 – Jul 11	55–85 days	Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost.
Cabbage	Apr 24 – May 8	—	May 15 – May 29	Jul 4 – Jul 18	60–100 days	Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost.
Brussels Sprouts	Apr 24 – May 8	—	May 22 – Jun 5	—	90–110 days	Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost.
Carrot	—	May 15 – May 29	—	Jun 20 – Jul 4	60–80 days	Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked.
Beet	—	May 15 – May 29	—	Jul 4 – Jul 18	50–65 days	Direct sow 2-4 weeks before last frost; tolerates light frost.
Radish	—	May 8 – May 22	—	Aug 1 – Aug 15	22–30 days	Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked.
Turnip	—	May 15 – May 29	—	Jul 4 – Jul 18	40–60 days	Cold-hardy; direct sow 2-4 weeks before last frost.
Onion	Apr 3 – Apr 17	—	May 15 – May 29	—	90–120 days	Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Garlic	—	—	—	Aug 15 – Aug 29	240–270 days	Fall-planted crop only; not planted in spring in most climates.
Potato	—	May 15 – May 29	—	—	70–120 days	Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated.
Sweet Potato	—	—	Jun 26 – Jul 10	—	90–120 days	Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive.
Asparagus	—	—	May 15 – May 29	—	730–1095 days	Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production.

Herbs
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Basil	May 1 – May 8	—	Jun 19 – Jun 26	—	50–70 days	Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm.
Cilantro	—	May 22 – Jun 5	—	Jul 18 – Aug 1	45–70 days	Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring.
Parsley	Apr 17 – May 1	—	May 29 – Jun 5	—	70–90 days	Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant).
Dill	—	May 22 – Jun 5	—	—	40–60 days	Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer.
Oregano	Apr 17 – May 1	—	Jun 12 – Jun 19	—	80–90 days	Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date.
Thyme	Apr 17 – May 1	—	Jun 12 – Jun 19	—	85–95 days	Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost.

Flowers
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Sunflower	—	Jun 19 – Jul 3	—	—	70–100 days	Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting.
Zinnia	May 15 – May 22	Jun 19 – Jul 3	Jun 19 – Jun 26	—	60–70 days	Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.
Marigold	May 1 – May 15	—	Jun 19 – Jun 26	—	45–60 days	Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed.
Cosmos	May 15 – May 22	Jun 19 – Jul 3	Jun 19 – Jun 26	—	60–90 days	Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.
Nasturtium	—	Jun 19 – Jul 3	—	—	50–65 days	Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed.
Dahlia	—	—	Jun 19 – Jul 3	—	90–120 days	Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive.

Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.

Frequently Asked Questions

When is the last frost in Evanston, WY?

Based on 1991–2020 NOAA climate normals for the EVANSTON 1 E, WY US station, the last spring frost in Evanston typically falls around June 12. A cautious gardener might wait until July 2 (only a 10% chance of a later frost), while May 26 marks an earlier, higher-risk planting date.

When is the first frost in Evanston, WY in fall?

The first fall frost in Evanston typically arrives around September 12. To stay safe, assume frost could start as early as August 26; in milder years it can hold off until September 25.

How long is the growing season in Evanston, WY?

Evanston's average frost-free growing season is about 90 days, running from the typical last spring frost (June 12) to the typical first fall frost (September 12).

What USDA hardiness zone is Evanston, WY in?

Evanston, WY is in USDA plant hardiness zone 5a, per the USDA's 2023 Plant Hardiness Zone Map. A classic four-season climate with cold winters and a solid summer growing season.