Comparing the Accuracy of the Stock Weber Smokey Mountain Thermometer to ChefsTemp S1

The Issue

The Weber Smokey Mountain is a popular and versatile cooker, but it has one major flaw – the stock thermometer. It’s downright inaccurate. I haven’t fired up my WSM in a few days, yet the stock thermometer currently reads 180-degrees Fahrenheit. When the bi-metal tip is dipped into a pot of boiling water, the needle slowly moves to 245-degrees.

I’m not the only one with a faulty thermometer – this is a widely discussed issue on many BBQ forums and social media sites. Luckily, they are easy to replace by simply unscrewing a single wing nut.

The Solution

I opted to go digital, and get a few extras with the ChefsTemp ProTemp S1 Smart Grill Temperature Controller Upgrade Package which comes with the Breezo V2 BBQ Temperature Control Fan, and a smart, Wi-Fi and Bluetooth connectable digital thermometer.

The ProTemp S1 Smart Grill Gauge Thermometer Hub is accurate to ±1°F, incredibly easy to install on your smoker and pair with your smartphone, and can track up to 4 wireless probes simultaneously.

The Comparison

I wanted to run a few tests to compare the S1 to the stock unit, and sticking them into a pot of boiling water showcased the S1’s accuracy right off the bat. The S1 read 212 degrees on the dot.

I realize boiling water doesn’t have much to do with proper BBQing – so I ran two more practical tests that pit masters can relate to.

I performed two cooks on my 22” WSM and swapped the thermometers several times during each cook to monitor the difference. I also setup a Maverick XR Pro Wired Thermometer on the top grate to give a baseline temperature reading where the food sat.

For each cook, I started with a freshly cleaned smoker, loaded the charcoal basket with a 16-pound bag of Kingsford Original charcoal briquettes (blue bag), similar sized chunks of hickory, and used the minion method to start the fire in the cooker. For each test, food was cooked on the top grate, and the lower cooking grate was removed.

For the low-and-slow test that involved the water pan, it was filled nearly to the top with cold tap water right after the coals were dumped in and the smoker was assembled.

For the higher heat 325-degree cook, the water pan was removed entirely.

During each cook, I kept the lid opening to a minimum, had the top vent fully open, two of the bottom vents completely shut, and one vent had the Breezo V2 BBQ Temperature Control Fan inserted into one of the ventilation holes, with the other two holes taped shut with the provided high-heat tape.

Tip: Get your Weber Smokey Mountain a smart & wireless temp control bundle here! 100% compatible!

The Tests

Test 1

Target Temp: 225

Food: Rack of spare ribs

Water pan: In

ChefsTemp Readings: 215-235

Maverick XR Pro Readings: 210-230

Stock Thermometer Readings: 250-275

Weather: Sunny, 75-degrees, light wind

Test 2

Target Temp: 325

Food: Whole chicken spatchcocked  

Water pan: Out

ChefsTemp Readings: 310–340

Maverick XR Pro Readings: 305-350

Stock Thermometer Readings: 350 (maxed out)

Weather: Sunny, 76-degrees, breezy

Test 3

Boiling Water (at sea level)

ChefsTemp Readings: 212

Maverick XR Pro Readings: 209

Stock Thermometer Readings: 245

Ambient Temperature Readings (on day 2) before firing up the smoker

ChefsTemp S1: 77

Maverick XR Pro: 78

Stock Thermometer: 190

National Weather Service Forecast: 76

Tip: Click here to learn more about testing a thermometer with boiling water, if you’re interested.

The Results

Between the boiling water test, the low-and-slow cook, and the high-heat cook, the results are pretty conclusive. The stock thermometer is regularly off by at least 30 degrees or more (and way off when not in use).

Of course, the stock thermometer and the ChefsTemps S1 sit high up in the dome, and heat rises, so a variance is expected when comparing these readings to the Maverick at grate level.

That being said, the ChefsTemp S1 does have a much longer stem at 3.5-inches, and during these experiments I found the readings of the S1 and Maverick weren’t too far apart.

A great feature of the ChefsTemp S1 paired with the Breezo fan is the ability to open an app and set the temperature. For both cooks, setting it to 225, and 325 had the smoker up to temp in no time. The S1 fluctuates a little as the fan cycles, but I found it stays within a 20 degree or so margin of the set temp.

The Maverick XR Pro confirmed the grate temperature hovered around that 225 mark.

Compare this to the stock analog thermometer, and you have to fiddle with the vents and keep a close eye on things. On top of that – you have no realistic reading of where your cooker is truly sitting at temp wise.

Another inconvenience of the stock thermometer, in my experience, is that it’s an analog dial, and in order to read it, you must be nearby.

Compare that the the ChefsTemp S1 with a large digital readout, and connectivity to a mobile phone app via Bluetooth and Wi-Fi – which allows you to check the temperature from just about anywhere.

Coupled with the Breezo Fan, and wireless probes – you can leave the lid closed more often, let the unit keep the ambient temp under control, and monitor the internal temperature of your food from the comfort of your couch.

With 40-hours of battery life, and an included charger – you don’t need to worry about the S1 unit dying in the middle of a cook. Installation is incredibly simple, all you have to do is take the wing nut off the back of the stock thermometer, pop it off, and just slide the new base unit in its place, and secure it with the provided washer and wing nut.

The ChefsTemp ProTemp S1 Smart Grill Temperature Controller Upgrade Package is worth the investment to anyone who wants more accurate temperature readings, an easy to use automated temperature control system, and the convenience of controlling your Weber Smokey Mountain from an app.