Frost Dates for Fairbanks, AK 99709

Last spring frost May 18 · First fall frost September 8 · 113 frost-free days · USDA Zone 3b

Frost probability for 99709

Frost10%50%90%
Spring (last frost)May 27May 18May 9
Fall (first frost)August 24September 8September 21

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (17.2 km away); the 50% date is the median year.

Frost dates by ZIP code in Fairbanks, AK

ZIPLast spring frost (50%)First fall frost (50%)Zone
99709May 18September 83b
99701May 29August 273a
99775May 25August 302b
99790May 25August 303b

Month by month in Fairbanks

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost).
MarchStart peppers and eggplant indoors 8–10 weeks before your last frost (around May 18). Start tomatoes about two weeks later, 6–8 weeks before last frost.
AprilStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
MayLast frost around May 18. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
JuneFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JulySuccession plant lettuce and greens. Keep beds weeded and watered consistently.
AugustFirst fall frost approaching (around September 8). Transplant fall brassicas. Sow spinach, arugula, and radishes.
SeptemberFirst frost around September 8. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
OctoberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
NovemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 113-day season

Frequently Asked Questions

What is the last frost date for Fairbanks, AK (ZIP 99709)?

The median last spring frost date for Fairbanks, AK (ZIP code 99709) is around May 18. 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 Fairbanks, AK?

The median first fall frost date for Fairbanks, AK is around September 8. 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 Fairbanks, AK?

The frost-free growing season in Fairbanks is about 113 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 Fairbanks, AK?

Based on frost date patterns, Fairbanks falls approximately in 3b. 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 Fairbanks, AK?

Start tomato seeds indoors 6–8 weeks before your last frost date (around May 18). For Fairbanks, that's roughly March 23 to April 6. Transplant outdoors 1–2 weeks after your last frost.

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