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When to plant in College, AK

USDA Zone 2b

College, Alaska frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.

With only about 111 frost-free days, College has a short season — start heat-lovers indoors early, favor quick-maturing varieties, and use row cover to stretch both ends. Zone 2b is cold — in College, most perennials must be fully hardy, and your frost dates set a tight window for tender annual vegetables.

Station · COLLEGE OBSY · 1.6 km
Last spring frost
May 18
50% chance · 32°F
First fall frost
September 6
50% chance · 32°F
Growing season
111 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for CollegeA year-band showing 32°F frost risk from January to December for College: last spring frost around May 18, first fall frost around September 6, about 111 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

Frost probability

COLLEGE OBSY · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are College’s own odds, recorded at COLLEGE OBSY.

Frost-probability curves for CollegeProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around May 18 and the first fall frost around September 6, giving about 111 frost-free days.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FJun 16May 31May 17Aug 11Aug 26Sep 7
32°FJun 1May 18May 7Aug 24Sep 6Sep 20
28°FMay 22May 7Apr 26Sep 5Sep 20Oct 1

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19
Fall sowopen now
Collards
June 28July 26
Fall sowopen now
Kale
June 28July 26
Fall sowopen now
Kohlrabi
June 28July 26
Fall sowopen now
Turnip
June 28July 26
Fall sowopen now
Arugula
July 12August 9
Fall sowopen now
Bok Choy
July 12July 26
Fall sowopen now
Chervil
July 12August 9
Fall sowopen now
Cilantro
July 12August 9
Fall sowopen now
Claytonia (Miner's Lettuce)
July 12August 9
Fall sowopen now
Corn Salad (Mâche)
July 12August 9
Fall sowopen now
Gai Lan (Chinese Broccoli)
July 12July 26
Fall sowopen now
Lettuce
July 12August 9
Fall sowopen now
Mizuna
July 12August 9
Fall sowopen now
Mustard Greens
July 12August 9
Fall sowopen now
Radish
July 12August 9
Fall sowopen now
Shungiku (Edible Chrysanthemum)
July 12July 26
Fall sowopen now
Spinach
July 12August 9
Fall sowopen now
Tatsoi
July 12August 9
Fall sowin 21 days
Garlic
August 9August 23
Fall sowin 21 days
Shallot
August 9August 23

Add these crops to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in College, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 4 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

COLLEGE OBSY
Primary
2 km · 182 m elevation
SPRING
May 18
FALL
Sep 6
UNIVERSITY EXP STN
2 km · 145 m elevation
SPRING
May 16
FALL
Sep 8
FAIRBANKS MIDTOWN
4 km · 134 m elevation
SPRING
May 13
FALL
Sep 10

College planting FAQ

When is the last spring frost in College, AK?

On average, the last spring frost in College is around May 18 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.

When is the first fall frost in College, AK?

Expect College's first fall frost near September 6 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.

What hardiness zone is College in?

College is in USDA hardiness zone 2b. In zone 2b, winters are cold — pick cold-hardy varieties and protect tender crops.

How long is the growing season in College?

There are roughly 111 frost-free days in College (a short growing season), running from the average last frost around May 18 to the first fall frost near September 6.

When should I plant tomatoes in College?

In College, start tomato seeds indoors around March 23–April 6, then transplant seedlings outdoors around May 25 once the danger of frost has passed.

Planting reminders

Never miss a window in College

An email when it’s time to start seeds, transplant, and sow — timed to College’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at COLLEGE OBSY, 2 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in College, AK — Frost Dates & Zone 2b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00502107. Retrieved from https://blissgarden.com/alaska/college.