Frost Dates for Coos Bay, OR 97420

Last spring frost April 2 · First fall frost November 16 · 228 frost-free days · USDA Zone 9a

Frost probability for 97420

Frost10%50%90%
Spring (last frost)May 4April 2February 26
Fall (first frost)October 15November 16December 19

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (32.4 km away); the 50% date is the median year.

Month by month in Coos Bay

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart peppers and eggplant indoors 8–10 weeks before your last frost (around April 2). Start tomatoes about two weeks later, 6–8 weeks before last frost.
MarchStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
AprilLast frost around April 2. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
MayFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JuneSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
JulyHarvest regularly to encourage production. Monitor for pests and disease.
AugustMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
SeptemberDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
OctoberFirst fall frost approaching (around November 16). Transplant fall brassicas. Sow spinach, arugula, and radishes.
NovemberFirst frost around November 16. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
DecemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.

What grows in a 228-day season

Frequently Asked Questions

What is the last frost date for Coos Bay, OR (ZIP 97420)?

The median last spring frost date for Coos Bay, OR (ZIP code 97420) is around April 2. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Coos Bay, OR?

The median first fall frost date for Coos Bay, OR is around November 16. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Coos Bay, OR?

The frost-free growing season in Coos Bay is about 228 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Coos Bay, OR?

Based on frost date patterns, Coos Bay falls approximately in 9a. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Coos Bay, OR?

Start tomato seeds indoors 6–8 weeks before your last frost date (around April 2). For Coos Bay, that's roughly February 6 to February 20. Transplant outdoors 1–2 weeks after your last frost.

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