How do you read a rain gauge accurately? Place the gauge in an open area away from obstructions, check it within 24 hours of a rain event, read the inner measuring tube at eye level from the bottom of the meniscus, record the measurement, and empty the gauge completely before the next event. The Stratus® Professional Precision Rain Gauge has a magnified inner tube that makes reading to 0.01-inch easy even in low light. Made in USA.
Tom's Quick Answer: Get eye level with the inner tube, read from the bottom of the curved water surface (the meniscus), write it down, and empty it. Takes 30 seconds. Do it within 24 hours of every rain event before evaporation affects the reading.
Tom's Real-World Advice
Reading a rain gauge sounds simple — and it is, once you know the two things most people get wrong. First, they read from the top of the meniscus instead of the bottom, which adds 0.02–0.05 inches to every reading. Second, they wait too long after a rain event and lose measurement to evaporation. The Stratus® Professional Precision Rain Gauge makes accurate reading easy — the inner measuring tube is narrow and magnified.
Step-by-Step: How to Read the Stratus® Professional Precision Rain Gauge
- Approach within 24 hours of the rain event. Evaporation begins immediately after rain stops.
- Get eye level with the inner measuring tube. Crouch or bend so your eyes are at the same height as the water level.
- Read from the bottom of the meniscus. Always read from the lowest point of the curve, not the edges.
- Read to the nearest 0.01 inch. The Stratus inner tube is marked in 0.01-inch increments.
- Record the measurement immediately. Write it down or log it in your CoCoRaHS account.
- Empty the gauge completely. Pour out all water from both the inner tube and the outer collection cylinder.
- Check the gauge is still level. A tilted gauge underreads rainfall. Check level monthly.
Common Reading Mistakes and How to Avoid Them
| Mistake | Effect on Reading | Fix |
|---|---|---|
| Reading from top of meniscus | Reads 0.02–0.05" high | Always read from bottom of curve |
| Reading from above eye level | Reads low | Get eye level with the water surface |
| Waiting more than 24 hours | Reads low (evaporation) | Check within 24 hours of rain stopping |
| Not emptying completely | Next reading reads high | Tip upside down, shake out residual drops |
| Gauge not level | Reads low | Check level monthly, adjust bracket |
| Gauge near obstructions | Reads low or high depending on wind | Mount 10+ feet from any structure or tree |
How to Use Your Reading to Adjust Garden Watering
- Tomatoes need 1–2 inches per week. If Stratus shows 0.75 inches fell, you need 0.25–1.25 more inches from supplemental watering through the Tomato Crater moat.
- After a heavy rain (1.5+ inches): Skip supplemental watering for 2–3 days.
- After a light shower (under 0.25 inches): Don't count it toward your weekly total — it barely penetrates the soil surface.
- During a heat wave: Increase your weekly target to 2+ inches.
Joining CoCoRaHS: Turn Your Reading Into Science
CoCoRaHS is a free volunteer network where home observers submit daily precipitation readings that go directly to NOAA. Your Stratus® Professional Precision Rain Gauge is the official CoCoRaHS gauge. Sign up at cocorahs.org and your data contributes to the national precipitation database.
FAQs
How do you read a rain gauge correctly?
Get eye level with the inner measuring tube, read from the bottom of the meniscus, record the measurement, and empty the gauge completely. Always read within 24 hours of a rain event.
What is the meniscus on a rain gauge?
The meniscus is the curved surface of water in a narrow tube. Always read from the lowest point of the curve for accurate measurement. Reading from the top adds 0.02–0.05 inches to every reading.
How soon after rain should I read my gauge?
Within 24 hours — sooner in hot weather. Evaporation begins immediately after rain stops.
How do I use rain gauge readings to water my garden?
Tomatoes need 1–2 inches per week. Subtract your Stratus reading from the weekly target to determine how much supplemental watering to deliver through the Tomato Crater moat.
What is CoCoRaHS and how do I join?
CoCoRaHS is a free volunteer precipitation observation network. Sign up at cocorahs.org, use your Stratus® Professional Precision Rain Gauge (the official CoCoRaHS gauge), and submit daily readings.
Shop Stratus® Professional Precision Rain Gauge →
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More Stratus Resources: Stratus Rain Gauge Hub | Shop Tomato Crater | Learn From Tom
