Grow cannabis in Tracy, CA

Growing cannabis in Tracy: a 37-degree drop between afternoon and night

Tracy's thermometer covers a lot of ground in a day. At the Tracy Carbona station, 5.9 miles away, a July afternoon averages 93°F and the night after it about 57°F, a fall of roughly 37 degrees. August and September keep nearly the same gap.

So when you plan your next run, which number are you planning for: the 93 or the 57?

California home grow rules (as of October 2026)

Adults 21 and over: yes. Plant limit: 6 living plants per private residence, however many adults live there.

Locked space, not visible from a public place; cities and counties can set reasonable rules for indoor grows (but cannot ban them) and may ban outdoor grows; a landlord may prohibit growing on a rental. Source: Department of Cannabis Control; conditions: Prop 64 text as passed in 2016 (H&S Code 11362.2 and 11362.45). Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.

A Tracy grow room built for both ends of the day

Use the night. With July lows near 57°F, air pulled in after dark is far cooler than the afternoon, so a tent whose lamps run overnight from June through September works with the weather. An intake fan on a timer, feeding that air into a garage tent while the lamp is on, does much of what an air conditioner would.

Then guard the afternoon. July brings about 23 days at 90°F or hotter and August about 21, roughly 80 a year in all. With the lamps dark through those hours, the tent only has to shed the building's heat: keep it off a sun-baked wall, insulate the garage door if you can, and leave the exhaust running.

The hot months are dry months. Humidity averaged 35 percent in June 2024 and 36 in July, so seedlings and new clones want a dome or humidifier for their first couple of weeks. September's 45 percent was the highest reading from June through October, still comfortable for buds; a garage that breathes outside air usually needs a canopy fan more than a big dehumidifier.

Winter nights carry real cold. Lows in December and January average about 36°F, and the Carbona site averages some 26 freezing nights a year, 11 of them in December. A garage tent wants a small heater on a thermostat and a heat mat for seedlings. January's 82 percent outdoor reading matters only if that garage is unheated and damp; heated rooms tend to run dry.

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	57	62	68	73	80	88	93	92	89	79	67	56
Avg low °F	36	39	42	45	50	55	57	56	54	48	41	36
Humidity %	82					35	36	39	45	39

Highs and lows: NOAA 1991 to 2020 normals, Tracy Carbona station (5.9 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.

Outdoor timing in San Joaquin County

The state limit is 6 living plants per private residence, however many adults live there, locked away out of view of public places, and cities and counties can regulate and may ban outdoor grows. Check Tracy's rules first. Where outdoor plants are allowed, get seeds going in the first half of March, March 4 to 18, and set them out from April 15, the date nights first average 45°F.

The cool nights frame the season too. Nights average 50°F or warmer only from May 14 to October 5, so a plant set out in mid April spends its first month in chilly air, and buds still swelling in October feel the cold again. You have about 207 days before November 8, the early date for the first fall frost. A variety that finishes by early October avoids most of those cold nights; the cost is ripening in September's 45 percent air rather than October's 39.

Last spring frost	Feb 25 in a typical year, Apr 6 to be safe (later only 1 year in 10)
First fall frost	Nov 26 typical, as early as Nov 8 (1 year in 10)
Frost-free season	about 272 days
Nights stay 50°F or warmer	May 14 to Oct 5
Start seeds or clones indoors	Mar 4 to Mar 18
Move plants outdoors	Apr 15 or later

What stays between you and your Tracy grow

Grow talk travels in a town where people run into each other on Central Avenue or at the Downtown Tracy Artwalk. Your grow journal does not have to travel with it.

Your Tracy grow journal gets encrypted on your own phone before it is uploaded. Should our servers ever be breached, the grow records inside would be scrambled, with no key beside them. That guards what you write down. What a neighbor sees over a fence, or smells on a still evening near Lincoln Park, is a separate job.

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 Tracy ask

How much cooler are Tracy nights than days in summer?

About 35 to 37 degrees from July through September at the Tracy Carbona station. July averages 93°F by day and about 57°F by night, so grow lights running at night get the coolest air.

When can I plant cannabis outside in Tracy?

From April 15, after a March 4 to 18 seed start indoors, if your local rules allow outdoor plants. Nights average 45°F from that date, and frost after April 6 comes only about one spring in ten.

Does Tracy get frost in winter?

Yes. The station averages about 26 freezing nights a year, most of them in December and January, and the first fall frost typically arrives around November 26.

Growing near Tracy

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