CannaGLAP
Grow cannabis in Juneau, AK
Growing cannabis in Juneau: a cool summer, then a September that never dries out
On paper, Juneau has a fair season. Frost usually holds off from about April 20 to October 22, roughly 183 days. Plants do not grow on paper. Downtown, the July high averages just 63°F, the average year brings no 90-degree days at all, and by September the daily humidity averages 92 percent.
So the useful question is not when the frost comes. It is how much of that frost-free stretch is warm enough, and dry enough, to grow in.
Adults 21 and over: yes. Plant limit: 6 per adult (3 or fewer mature); 12 per dwelling (6 or fewer mature).
Not visible to the public; reasonable security; property you lawfully possess or with consent. Source: AS 17.38.030. Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.
Juneau indoors: dry the air first, then warm it
Moisture is the job in every Juneau grow room. July averages 89 percent humidity, August 83, September 92 and October 87, about 90 percent across the two months when photoperiod flowers are at their densest. A tent pulls that air in every time its fan runs. Size a dehumidifier for the whole room, not just the tent, and let it work hardest through late flower and the dark period, when cooling air drops its water onto the buds.
Heat almost never needs fighting, so the lamp becomes your most useful heater. July lows sit near 52°F, and January lows near 27°F. Time the light period for the coldest hours, lift pots off a chilly basement or garage floor, and keep seedlings on a mat. Every truck arrives by barge, so order a spare fan, filters and dehumidifier parts before you need them, not the week one fails.
Check the thickest buds by opening one. In air this wet, rot starts at the core of a dense cola and reaches the surface last. Thin the inner branches, keep air moving below the canopy, not only across the top, and give each plant room. A strain known for mold resistance is worth more here than one known for size.
Heater safety: use one with tip-over and overheat shutoff, plug it straight into a wall outlet (not an extension cord or power strip), and keep it a few feet from tent fabric and plants.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 37 | 39 | 49 | 57 | 62 | 63 | 62 | 56 | 48 | 40 | 36 |
| Avg low °F | 27 | 28 | 30 | 36 | 43 | 49 | 52 | 51 | 46 | 39 | 32 | 29 |
| Humidity % | 74 | 79 | 89 | 83 | 92 | 87 |
Highs and lows: NOAA 1991 to 2020 normals, Juneau Dwtn station (0.4 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Juneau's outdoor season is set by cold nights
Alaska's conditions: keep plants out of public view, use reasonable security, and grow only on property that is lawfully yours or where the owner has given consent. A secured greenhouse suits Juneau better than an open bed. Start seeds from April 13 to April 27; plants can go out from May 25, when nights first average 45°F. Those nights last until about September 21, roughly 133 days, and nights at 50°F or warmer run only from about June 26 to August 22.
Frost is not what ends a Juneau season; cold, wet nights are. Choose fast autoflowers, keep the rain off them with a roof or greenhouse, and harvest before the 92 percent month does its damage.
| Last spring frost | Apr 20 in a typical year, May 5 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Oct 22 typical, as early as Oct 5 (1 year in 10) |
| Frost-free season | about 183 days |
| Nights stay 50°F or warmer | Jun 26 to Aug 22 |
| Start seeds or clones indoors | Apr 13 to Apr 27 |
| Move plants outdoors | May 25 or later |
| Season note | Frost can arrive before mid October here: long flowering plants may not finish outdoors |
A town with no road in, and a log nobody reads
Juneau is a small town with no road in, and news travels. Someone at the Saturday Juneau Public Market may want to know what you grow and whether it made it through September. Sharing a tip costs nothing. Sharing the record is different, because a damp Juneau season took real work to write down.
Before a single entry leaves your phone, Canna GLAP encrypts it. Anyone who forced a way into our servers would find grow records they could not open, and no key on our side to open them. The numbers from your downtown Juneau grow stay out of reach.
What is encrypted: your plants, notes, photos, feed logs and harvests. What is not: account details (such as your email, name and plan), a grow name or town if you type one, your team, and your sensors' names. The full list: what a hacker would get.
Questions growers in Juneau ask
Do I need a dehumidifier to grow cannabis in Juneau?
Yes, for nearly any flower room. Humidity averages about 90 percent across September and October, and even July averages 89.
Can you grow cannabis outdoors in Juneau?
Yes, if plants are hidden from the public, reasonably secured and on land you lawfully hold or have the owner's consent to use. Expect about 133 days from May 25, cool nights and heavy late-season damp, so fast autoflowers under a roof do best.
Is it ever too hot to grow cannabis in Juneau?
Almost never. The average year has no days at 90°F, and the warmest month, July, averages a 63°F high, so a tent can run its lights whenever the room is coldest.
Growing near Juneau
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