What is the best hygrometer for drying cannabis?

The SensorPush HT.w is the best hygrometer for drying cannabis. It logs temperature and humidity over time, alerts your phone when the room drifts outside your set range, and carries a rated accuracy of ±3% RH. On a tight budget, the Govee H5075 handles the same job for about $15.

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Skip the analog dial gauges sold at grow shops. A digital sensor with a data log shows how fast your room dries, and that speed decides whether the flower smells like pine or like hay.

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The five picks at a glance

1. SensorPush HT.w: best overall

SensorPush built the HT.w for people who want records, not a glance. The sensor samples temperature and relative humidity, stores readings onboard, and syncs to a phone app over Bluetooth.

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Add the Wi-Fi gateway and the HT.w sends a text or email the moment your drying room crosses 65% RH or 75°F. That matters at 2 a.m., when mold starts and you are asleep.

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Rated accuracy sits at ±3% RH, which is tight enough for a 7 to 14 day dry. The trade-off is price. Each sensor costs around $50, and the gateway is a separate buy.

Who should buy it

Growers drying more than a pound, anyone who leaves the house during a dry, and people who want a chart of every run. The log also helps you repeat a good dry next season.

2. Govee H5075: best budget

Govee's small Bluetooth hygrometer costs about $15 and reads within a few points of a lab reference in most published user tests. The app graphs temperature and humidity and keeps a history you can review after the dry.

Range is the weak spot. Bluetooth fades through walls, so your phone has to stay near the tent. It also runs on replaceable batteries rather than a built-in cell.

Who should buy it

Home growers with one tent or one drying closet. Buy two, set one at canopy level and one near the floor, and you will spot a humidity pocket before it ruins the top colas.

3. Inkbird IBS-TH2: best for tight spaces

The IBS-TH2 is the size of a matchbox, so it fits between hanging branches or inside a tote. Inkbird's app logs readings and exports CSV files if you like spreadsheets.

The probe version adds a sensor on a cable. Drop the probe into a curing jar, leave the body outside, and you read the jar's internal humidity without opening the lid.

Accuracy lands in the ±3% to ±5% RH range depending on the unit. Test it before you trust it with a full harvest.

4. ThermoPro TP357: best big display

The TP357 shows large digits you can read from across the room and pairs with a phone app for history. It costs under $20 and runs on one AAA battery.

ThermoPro lists accuracy in the ±2% RH range for this model, though field results vary between units. It suits a drying room where you check the number two or three times a day and do not need alerts.

5. Caliber IV: best for curing jars

The Caliber IV was built for cigar humidors, which need the same 58% to 62% window as curing cannabis. It reads in 1% steps and has a calibration dial you turn with a small screwdriver.

It is not Bluetooth and it does not log. You pay for a stable sensor and a clear screen. For jar burping, that is often all you need.

What humidity and temperature should you target?

Dry cannabis at 60°F to 70°F and 55% to 65% relative humidity. Keep the room dark and the air moving with a small fan pointed away from the buds.

A slow dry takes 7 to 14 days. Push below 55% RH and the buds dry on the outside while the stems stay wet, which invites mold in the jar. Run above 65% RH and mold wins the race.

After the dry, cure in sealed jars at 58% to 62% RH. A two-way humidity pack holds that range while you burp the jars each day for the first week.

How accurate does the hygrometer need to be?

±3% RH is good. ±5% RH works if you know the offset. A cheap sensor that reads 3 points high still keeps you safe once you note the gap and account for it.

Accuracy matters most near the edges. At a true 66% RH with a meter that reads 3 points low, the display shows 63% and the room sits in mold territory.

How do you calibrate a hygrometer?

  1. Fill a bottle cap with table salt and add a few drops of water until it forms a paste.
  2. Put the cap and the hygrometer in a sealed bag or jar, and keep them apart.
  3. Wait 8 to 12 hours at room temperature.
  4. Read the display. A saturated salt solution holds about 75% RH at 75°F.
  5. Note the gap. If the meter shows 72%, it reads 3 points low.

A Boveda 75% calibration kit does the same job with less mess and takes about 24 hours. Recheck every few months, since low-cost sensors drift over time.

Frequently asked questions

Can I dry cannabis without a hygrometer?

You can, and people do. You will guess at the stall point and the jar humidity. A $15 sensor removes the guesswork, so the math favors buying one.

Where should I place the hygrometer in the drying room?

Put it at bud level, in the middle of the canopy, away from the fan and away from the wall. Humidity stratifies, so a reading at the ceiling tells you little about the flowers.

Do I need Wi-Fi, or is Bluetooth enough?

Bluetooth works if you sleep near the drying room and check the app. Wi-Fi gateways cost more but send alerts when you are away, which is the point of an alarm.

Should I use one hygrometer per jar?

For small grows, one probe hygrometer that you move between jars is enough. Commercial cure rooms run a sensor in each container instead.

Which one should you buy?

Start with the SensorPush HT.w if you want alerts and records. Take the Govee H5075 if you want a cheap second opinion at canopy level. Add the Caliber IV when you move from drying to curing, and salt-test every sensor before the first chop.