--- product_id: 165743724 title: "SC42 Professional Digital Hygrometer Indoor Room Thermometer" brand: "smartro" price: "$43.66" currency: USD in_stock: true reviews_count: 13 category: "Smartro" url: https://www.desertcart.us/products/165743724-sc42-professional-digital-hygrometer-indoor-room-thermometer store_origin: US region: United States of America --- # ±0.5°F & ±2%RH accuracy 2x AAA battery powered 10-sec update speed SC42 Professional Digital Hygrometer Indoor Room Thermometer **Brand:** smartro **Price:** $43.66 **Availability:** ✅ In Stock ## Summary > 🌡️ Stay flawlessly in control of your indoor climate — because comfort is the new luxury. ## Quick Answers - **What is this?** SC42 Professional Digital Hygrometer Indoor Room Thermometer by smartro - **How much does it cost?** $43.66 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/165743724-sc42-professional-digital-hygrometer-indoor-room-thermometer) ## Best For - smartro enthusiasts ## Why This Product - Trusted smartro brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Precision Swiss Sensors:** Industrial-grade accuracy with updates every 10 seconds keeps you ahead of indoor climate shifts. - • **24-Hour & All-Time Records:** Track max/min temperature and humidity trends to optimize your living or workspace comfort. - • **Manual Calibration Support:** Fine-tune sensor accuracy to your environment for flawless data you can trust. - • **Versatile Mounting Options:** Magnetic back, retractable stand, and wall mount hole let you place it anywhere with style. - • **Vivid 3.5'' Backlit Display:** Large HD screen with touch-activated backlight ensures effortless readings day or night. ## Overview The SMARTRO SC42 Professional Digital Hygrometer combines Swiss precision sensors with a large, easy-to-read backlit display, delivering temperature accuracy within ±0.5°F and humidity within ±2%RH. It updates readings every 10 seconds and records 24-hour and all-time max/min data, helping you maintain optimal indoor comfort. With versatile mounting options and manual calibration, it’s perfect for any room, from nurseries to wine cellars. Powered by 2 AAA batteries, it’s a reliable, stylish tool for millennial professionals who demand precision and convenience. ## Description desertcart.com: SMARTRO SC42 Professional Digital Hygrometer Indoor Room Thermometer | Humidity Gauge Pro Accuracy Calibration : Patio, Lawn & Garden Review: Extremely accurate and easy to read — best hygrometer I’ve owned - I picked up the SMARTRO SC42 Professional Digital Hygrometer about two months ago to monitor my master bedroom because of bathroom with shower. This thing is impressive right out of the box. The 3.5" LCD screen is large and clear, with big digits that are easy to read even from across the room. The touch-activated backlight is a nice touch — it lights up for about 10 seconds when you tap the top, perfect for checking at night without turning on a lamp. Accuracy seems spot-on. It uses industrial-grade sensors (Swiss-made, according to the specs) and updates every 10 seconds. I compared it side-by-side with a couple of other thermometers/hygrometers I own, and it consistently matched or beat them. Temperature is within ±0.5°F and humidity within ±2% RH, which is excellent for this price range. I love that it shows 24-hour and all-time high/low records too — super helpful for tracking how my AC or humidifier is doing. It also has a comfort indicator that tells you if the room is too dry, too humid, or just right. Setup was basically plug-and-play (2x AAA batteries, not included). It comes with a stand, magnetic back, and hanging hole, so you can place it anywhere. No real complaints so far — battery life is solid, and it feels well-built. If you want a reliable indoor consumer thermometer/hygrometer this one is a winner. Highly recommend. Review: Absolutely A Great Purchase! Highly Recommend! - Just got it today based on all of the reviews and I'm extremely Happy with my purchase! Super Easy to set up, literally I put the batteries in and it did whatever it had to do on its own! I Love that it comes with magnets attached and a little stand. I purchase the two-pack and stuck one to the fridge via the magnet and one in another area on its stand. Love the light button to make it bright when you need to see it, Love the Large Numbers, Temperature monitoring was spot on.... I can tell this will function perfectly and the batteries will last quite a while because the light goes to a dimmer mode until you need to make it brighter. We have Golden Retrievers with double coat fur and I'm always cold and can't tell if their rooms are too hot & humid... so these are perfect for each area they are in so I can keep them comfortable! Just got them today and already Love them! Great Price too! I would Highly Recommend and would purchase again! It was delivered FAST too. ## Features - The Best Industrial Grade Accuracy: Humidity gauge with built-in Swiss sensors, it detects subtle humidity and temperature changes and updates readings in each 10 seconds. Temperature tolerance is within 0.5℉(-4 to 158℉) and humidity is 2%RH (1 to 99% RH). The digital hygrometer is pre-calibrated for accurate temperature and humidity measurement. - Easy-to-Read Backlit Display: Temperature and humidity monitor with 3.5'' large HD LCD screen. A simple touch on the top will turn on backlit for 10 seconds. Clear and power-saving, reading more easily under weak backlit. Reliable operating buttons on the back for manual setting or °F/°C switching. Note: The backlit in the pictures is all in ON state. The backlit is not always on. - 24 Hours All-time Max Min Records: The room thermometer displays high and low records for the past 24 hours and All-time; Indoor thermometer measure conditions and identify changes in temperature and humidity instantly. Comfort Indicator ensures proper humidity control, helping you to maintain a comfortable atmosphere in your home. - Wide Applications with More Mounting Options: With a retractable stand, two powerful magnets and a wall-mount hole, this digital thermometer indoor can be easily attached to your refrigerator, wall or placed on a table. Suitable for baby’s room, nursery, office, closet, incubator, greenhouse, garden, wine cellar, basement critter terrarium etc. Note: This thermometer cannot connect to phones. - Calibration Supported: The monitor can be manually calibrated to improve data readings when product placement or environmental factors impact your data accuracy. Powered by 2x1.5v AAA batteries (not included). ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B07YY1FB9D | | Battery Description | 2x 1.5v AAA batteries | | Best Sellers Rank | #2,587 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #5 in Weather Hygrometers | | Brand | SMARTRO | | Brand Name | SMARTRO | | Color | black | | Customer Reviews | 4.6 out of 5 stars 7,045 Reviews | | Included Components | 1 thermometer 1 manual | | Item Dimensions W x H | 3.4"W x 3.4"H | | Item Weight | 0.13 kg | | Manufacturer | SMARTRO | | Model | SC42 | | Mounting Type | Wall Mount | | Number of Items | 1 | | Operating Humidity | 1-99% with a +/- 2%RH tolerance | | Part Number | SC42EUK | | Product Dimensions | 3.4"W x 3.4"H | | Temperature Accuracy | +/-0.5 °F | | Temperature Reading Accuracy | plus_minus_0_point_2_degrees_celsius | | Unit Count | 1 Count | | Upper Temperature Range | 158 °F | | Voltage | 3 | | Warranty Description | 13-month warranty except for artificial damages | ## Product Details - **Battery Description:** 2x 1.5v AAA batteries - **Brand:** SMARTRO - **Color:** black - **Item Weight:** 0.13 kg - **Product Dimensions:** 3.4"W x 3.4"H ## Images ![SC42 Professional Digital Hygrometer Indoor Room Thermometer - Image 1](https://m.media-amazon.com/images/I/71J0pGYeMFS.jpg) ![SC42 Professional Digital Hygrometer Indoor Room Thermometer - Image 2](https://m.media-amazon.com/images/I/71xxttfrSUL.jpg) ![SC42 Professional Digital Hygrometer Indoor Room Thermometer - Image 3](https://m.media-amazon.com/images/I/71kMBSbg7vL.jpg) ![SC42 Professional Digital Hygrometer Indoor Room Thermometer - Image 4](https://m.media-amazon.com/images/I/71si35LZMXL.jpg) ![SC42 Professional Digital Hygrometer Indoor Room Thermometer - Image 5](https://m.media-amazon.com/images/I/81-O4kKqaNL.jpg) ## Available Options This product comes in different **Number Of Items** options. ## Questions & Answers **Q: Does this display Humidity or does it display Relative Humidity?** A: From the Amazon product page, Specifications: "Humidity Range: 1~99%RH(relative humidity)". The Amazon page mentions "RH" at least 9 times, strongly suggesting that is what it displays. Additionally, humidity is the amount of water vapor in a unit volume of air (independent of temperature) which is expressed in kilograms per cubic meter. Relative Humidity is the PERCENTAGE of the maximum amount of water vapor in the air, possible at that temperature. Because the Hygrometer reports a percentage, not a mass per volume, there can be no confusion. RH is what you want for controlling comfort and environmental conditions (mold growth, etc,). **Q: Can this be calibrated if needed?** A: You can only calibrate if you have a standard that is accurate. You can adjust the reading up and down. I have 7 of these so I put them all in the same room for about 6 hours and I adjusted mine so it matched the rest. The rest were within 2 of each other, this one was 4 so I made it like the others. **Q: can you make the light stay on?** A: Not as far as I can see. Just a very light tap on the top of the frame will light it up for about ten seconds. That seems more than enough IMHO. If left on too much, the battery would drain sooner. Just a very very light tap. **Q: Your product information states: "calibration certification from aerospace institute for metrology and measurement technology" missing cert. doc?** A: I have never looked for any certification's. I did a comparison test with 4 different instruments and liked this model best, so I purchased 4 or 5 of them. They have been working fine in my home and hobby woodworking shop. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Extremely accurate and easy to read — best hygrometer I’ve owned *by M***I on May 4, 2026* I picked up the SMARTRO SC42 Professional Digital Hygrometer about two months ago to monitor my master bedroom because of bathroom with shower. This thing is impressive right out of the box. The 3.5" LCD screen is large and clear, with big digits that are easy to read even from across the room. The touch-activated backlight is a nice touch — it lights up for about 10 seconds when you tap the top, perfect for checking at night without turning on a lamp. Accuracy seems spot-on. It uses industrial-grade sensors (Swiss-made, according to the specs) and updates every 10 seconds. I compared it side-by-side with a couple of other thermometers/hygrometers I own, and it consistently matched or beat them. Temperature is within ±0.5°F and humidity within ±2% RH, which is excellent for this price range. I love that it shows 24-hour and all-time high/low records too — super helpful for tracking how my AC or humidifier is doing. It also has a comfort indicator that tells you if the room is too dry, too humid, or just right. Setup was basically plug-and-play (2x AAA batteries, not included). It comes with a stand, magnetic back, and hanging hole, so you can place it anywhere. No real complaints so far — battery life is solid, and it feels well-built. If you want a reliable indoor consumer thermometer/hygrometer this one is a winner. Highly recommend. ### ⭐⭐⭐⭐⭐ Absolutely A Great Purchase! Highly Recommend! *by R***M on May 12, 2026* Just got it today based on all of the reviews and I'm extremely Happy with my purchase! Super Easy to set up, literally I put the batteries in and it did whatever it had to do on its own! I Love that it comes with magnets attached and a little stand. I purchase the two-pack and stuck one to the fridge via the magnet and one in another area on its stand. Love the light button to make it bright when you need to see it, Love the Large Numbers, Temperature monitoring was spot on.... I can tell this will function perfectly and the batteries will last quite a while because the light goes to a dimmer mode until you need to make it brighter. We have Golden Retrievers with double coat fur and I'm always cold and can't tell if their rooms are too hot & humid... so these are perfect for each area they are in so I can keep them comfortable! Just got them today and already Love them! Great Price too! I would Highly Recommend and would purchase again! It was delivered FAST too. ### ⭐⭐⭐⭐⭐ Great Product *by K***K on August 3, 2026* So far so good, worked great right out of the box. Love that I can see humidity AND temp all in one place. ## Frequently Bought Together - SMARTRO SC42 Professional Digital Hygrometer Indoor Thermometer Room Humidity Gauge Pro Accuracy Calibration - ThermoPro TP55 Digital Indoor Hygrometer Thermometer, 4-Inch Temperature / Humidity Monitor with Touchscreen and Backlit, Indoor Room Thermometer / Humidity Meter for House Home Greenhouse - ThermoPro TP50 Digital Hygrometer Indoor Thermometer Room Thermometer and Humidity Gauge with Temperature Monitor --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.us/products/165743724-sc42-professional-digital-hygrometer-indoor-room-thermometer](https://www.desertcart.us/products/165743724-sc42-professional-digital-hygrometer-indoor-room-thermometer) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-08-12*