Frost Dates & Planting Calendar for Oro Valley, AZ

The average first fall frost in Oro Valley, AZ is November 11, and the average last spring frost is April 2, giving a growing season of about 222 days.

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

Last Spring Frost

April 2

Safe Apr 18 Typical Apr 2 Risky Mar 16

First Fall Frost

November 11

Safe Oct 26 Typical Nov 11 Risky Nov 29

Growing Season

222 days

Typical last frost to typical first frost.

USDA Hardiness Zone

Zone 9a

Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.

Data: NOAA station CATALINA SP, AZ US, 4.5 km away.

— days until the typical last spring frost

How Oro Valley Compares

Oro Valley's typical last spring frost (Apr 2) comes later than in 78% of the 69 Arizona cities we track.
Its 222-day growing season is 76 days shorter than the Arizona median of 298 days.
Compared with Casas Adobes (8 km away), Oro Valley's last spring frost comes 35 days later than Casas Adobes's, and its first fall frost arrives 23 days earlier.
June is the warmest month (average high 101°F) and January the coldest (average low 31°F).

Monthly Temperatures

Avg. high Avg. temp Avg. low

Planting Calendar

Vegetables
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Tomato	Feb 5 – Feb 19	—	Apr 9 – Apr 16	—	60–85 days	Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed.
Pepper	Jan 22 – Feb 5	—	Apr 9 – Apr 23	—	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	Jan 22 – Feb 5	—	Apr 16 – Apr 23	—	65–85 days	Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant.
Cucumber	Mar 5 – Mar 12	Apr 9 – Apr 16	Apr 9 – Apr 16	—	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	Mar 12 – Mar 19	Apr 9 – Apr 23	Apr 9 – Apr 16	—	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	Mar 5 – Mar 12	Apr 9 – Apr 23	Apr 9 – Apr 16	—	80–110 days	Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates.
Pumpkin	—	Apr 9 – Apr 23	—	—	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	Mar 5 – Mar 12	—	Apr 16 – Apr 23	—	70–90 days	Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.
Cantaloupe	Mar 5 – Mar 12	—	Apr 16 – Apr 23	—	70–90 days	Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting.
Corn	—	Apr 2 – Apr 16	—	—	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	—	Apr 2 – Apr 16	—	—	50–65 days	Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush.
Pea	—	Feb 19 – Mar 5	—	—	55–70 days	Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Lettuce	—	Mar 5 – Mar 19	—	Sep 16 – Sep 30	45–60 days	Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts.
Spinach	—	Feb 19 – Mar 5	—	Sep 16 – Sep 30	40–50 days	Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Kale	—	Mar 5 – Mar 19	—	Sep 2 – Sep 16	50–65 days	Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants.
Arugula	—	Mar 5 – Mar 19	—	Sep 30 – Oct 7	30–40 days	Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks.
Swiss Chard	—	Mar 12 – Mar 26	—	—	50–60 days	Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too.
Broccoli	Feb 12 – Feb 26	—	Mar 12 – Mar 19	Sep 9 – Sep 16	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	Feb 12 – Feb 26	—	Mar 19 – Mar 26	Sep 2 – Sep 9	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	Feb 12 – Feb 26	—	Mar 5 – Mar 19	Sep 2 – Sep 16	60–100 days	Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost.
Brussels Sprouts	Feb 12 – Feb 26	—	Mar 12 – Mar 26	—	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	—	Mar 5 – Mar 19	—	Aug 19 – Sep 2	60–80 days	Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked.
Beet	—	Mar 5 – Mar 19	—	Sep 2 – Sep 16	50–65 days	Direct sow 2-4 weeks before last frost; tolerates light frost.
Radish	—	Feb 26 – Mar 12	—	Sep 30 – Oct 14	22–30 days	Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked.
Turnip	—	Mar 5 – Mar 19	—	Sep 2 – Sep 16	40–60 days	Cold-hardy; direct sow 2-4 weeks before last frost.
Onion	Jan 22 – Feb 5	—	Mar 5 – Mar 19	—	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	—	—	—	Oct 14 – Oct 28	240–270 days	Fall-planted crop only; not planted in spring in most climates.
Potato	—	Mar 5 – Mar 19	—	—	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	—	—	Apr 16 – Apr 30	—	90–120 days	Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive.
Asparagus	—	—	Mar 5 – Mar 19	—	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	Feb 19 – Feb 26	—	Apr 9 – Apr 16	—	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	—	Mar 12 – Mar 26	—	Sep 16 – Sep 30	45–70 days	Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring.
Parsley	Feb 5 – Feb 19	—	Mar 19 – Mar 26	—	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	—	Mar 12 – Mar 26	—	—	40–60 days	Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer.
Oregano	Feb 5 – Feb 19	—	Apr 2 – Apr 9	—	80–90 days	Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date.
Thyme	Feb 5 – Feb 19	—	Apr 2 – Apr 9	—	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	—	Apr 9 – Apr 23	—	—	70–100 days	Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting.
Zinnia	Mar 5 – Mar 12	Apr 9 – Apr 23	Apr 9 – Apr 16	—	60–70 days	Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.
Marigold	Feb 19 – Mar 5	—	Apr 9 – Apr 16	—	45–60 days	Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed.
Cosmos	Mar 5 – Mar 12	Apr 9 – Apr 23	Apr 9 – Apr 16	—	60–90 days	Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.
Nasturtium	—	Apr 9 – Apr 23	—	—	50–65 days	Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed.
Dahlia	—	—	Apr 9 – Apr 23	—	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 Oro Valley, AZ?

Based on 1991–2020 NOAA climate normals for the CATALINA SP, AZ US station, the last spring frost in Oro Valley typically falls around April 2. A cautious gardener might wait until April 18 (only a 10% chance of a later frost), while March 16 marks an earlier, higher-risk planting date.

When is the first frost in Oro Valley, AZ in fall?

The first fall frost in Oro Valley typically arrives around November 11. To stay safe, assume frost could start as early as October 26; in milder years it can hold off until November 29.

How long is the growing season in Oro Valley, AZ?

Oro Valley's average frost-free growing season is about 222 days, running from the typical last spring frost (April 2) to the typical first fall frost (November 11).

What USDA hardiness zone is Oro Valley, AZ in?

Oro Valley, AZ is in USDA plant hardiness zone 9a, per the USDA's 2023 Plant Hardiness Zone Map. Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.