Climalytic Instruments TROPO Precipitation Gauge Review

Editor's Choice

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• Easy to read
• Very accurate, even in windy conditions
• Larger capacity

• You pay for these features

While weather gadgets don’t have the upgrade cycle of an iPhone, manufacturers improve their products frequently in an attempt to get you to part with your hard-earned money. This is why I initially said “yeah, okay” when Climalytic Instruments pitched us on the TROPO Precipitation Gauge. It’s a rain gauge, can you really improve on such a basic weather instrument?

Then I learned a few things I didn’t know. The Stratus Precision Rain Gauge is 50(!) years old this year. While much more accurate than other rain gauge designs, the Stratus design isn’t perfect, resulting in some small but built-in inaccuracy. While rain gauges don’t need to change much, there’s obviously been at least some advancement in rain gauge designs over the past half-century.

With this in mind, Colorado-based meteorologist Tye Parzybok set out to create a rain gauge that not only is more accurate but with features aimed squarely at addressing some of the annoyances weather observers experience, both with the Stratus and other dual-cylinder gauges. It sounds like a fool’s errand, but I think they’ve actually done both.

Fair warning though: the TROPO is not cheap. At $100, this is not for the everyday consumer. But for its primary target audience — CoCoRAHS — and accuracy-conscious weather watchers, spending the extra $50 may be worth it.

Stratus vs. TROPO – What’s the difference?

Before diving into the review, I assume most want to know what the difference is between the two upfront. Both use a dual-cylinder design, aiming to capture rainfall first in the inner cylinder and collect any additional rainfall in the larger outer cylinder. However, the TROPO is significantly larger, with a 13.5-inch capacity vs. 11 inches for the Stratus.

While 99% of us will never need that kind of capacity, increasing that also makes the inner cylinder larger. While the TROPO’s inner cylinder still measures just the first inch that falls, the larger size spreads the measurement hash marks apart on the cylinder wall, making it easier to read. While I never had significant issues reading measurements, I could see where those with vision problems might have had some difficulty.

There are also a host of what I’d call “convenience features,” all aimed at making use of the gauge much easier than its predecessor. It’s here where the TROPO really sets itself apart and makes a stronger case for the premium price tag.

Setting Up and Using the TROPO Precipitation Gauge

Climalytic includes a vertical surface mount which the TROPO can be slid on and off of during measurements. We do recommend you follow our installation guide for weather stations to ensure the most optimal readings. But inside the box, you’ll not only find the surface mount, but a handle too. This slides into the same spot where you mount the gauge.

But that’s not all: the outer gauge has a second surprise: a spout. For anyone who’s used the Stratus, you’ll think this is brilliant. The former prevents the cylinder from slipping out of your hand during transport or pouring, the latter makes sure the water makes it into your inner cylinder rather than on your kitchen counter.

Don’t want to use the handle? The TROPO has textured grips placed in the middle of the gauge, which work just as well.

Most aren’t ready for the weight of a couple of inches of water. In the heaviest rainstorms, measurements with the Stratus are a two-person job, one to hold the outer cylinder with BOTH hands, the other to ensure the inner cylinder doesn’t tip over as you’re pouring it in. We were lucky enough to have a torrential rainstorm during the test, so we experienced just how easy (and a one-person job) it is to take measurements using the handle and spout features of the TROPO.

I also appreciated the addition of bird spikes to the gauge cap. The Stratus without regular cleaning becomes a bird toilet — these spikes positioned closely around the rim of the funnel will ensure that’s no longer a problem. Our TROPO was outside for the test for a full week, and it returned completely clean — something that would never happen with the Stratus.

The Tons of Minor Enhancements All Add Up

Much of the rest of what the TROPO offers over the Stratus is far less significant, but together further separate it from other dual-cylinder rain gauges. For example, the walls of the funnel itself are much steeper than the Stratus, which in theory should improve the capture of rainfall in windy conditions. The funnel also ‘snaps’ on to prevent blow-offs, which is a known issue for the Stratus in extremely windy weather.

The outer cylinder also features indentations inside on the bottom which allow you to secure the inner cylinder better after measurements. With the Stratus, there’s nothing on the bottom to keep it from moving around. Often, I’d find myself just trying to place it as best as I could and quickly putting the cap on. Sometimes that would work and it would nudge the inner cylinder into place if necessary — but not always.

Then there’s the actual construction of the gauge itself. Climalytic decided to use polycarbonate, which features better UV and weather resistance. It’s also more durable, too, as weakened plastic can crack if the temperature changes drastically, or water freezes inside the tube. While the Stratus is also made of polycarbonate, we’ve found over time to become cloudy much like traditional plastic would.

We’ve only had the TROPO for a few weeks, so it’s very difficult to judge the durability of the gauge right now, but we’ll update this review if necessary.

Accuracy

All of the above functionality wouldn’t matter much if the TROPO wasn’t demonstratively more accurate than the Stratus. In our tests, the measurements from a multi-day rainstorm were fairly similar, but the TROPO measured .01″ less — 2.43″ vs. 2.44″. That is to be expected, as the studies have shown that the Stratus overmeasures rainfall by approximately 2.5%. Here the difference is minuscule — just .4% — but others with more long-term experience reported similar results, with the Stratus overmeasuring about .03″ for every inch of rainfall measured.

Now, in fairness, there is also a margin of error that you must deal with in the actual measurement process. As I stated at the beginning, the Stratus isn’t as easy to read as the TROPO, so there’s a non-zero chance I may have read the Stratus incorrectly and the true difference is more significant. Some of the changes in the TROPO are also aimed at eliminating human error, too.

Final Thoughts

The TROPO is not a consumer rain gauge, nor is it intended to be. It’s every bit a precision meteorological instrument, designed by a meteorologist whose scientific focus has been on gathering precise precipitation data for much of his career (and one of the first CoCoRAHS observers, too). We’d still recommend the Stratus Rain Gauge above any store-bought rain gauge, which is often wildly inaccurate. And CoCoRAHS says that you don’t have to buy the gauge — the Stratus will meet their requirements for the foreseeable future.

That said, the convenience features are what really sold me on the TROPO. It’s obvious that the inventor participated in the program, as some of the “fixes” are common complaints about using the Stratus and taking weather observations. The changes to the design make it a more accurate gauge, and accuracy is something that most weather observers are concerned with for good reason.

If you have the money, the TROPO gets our full-throated endorsement. It’s that good.