How to read a rain gauge
Updated: October 2026
The tube in the border becomes a record only when you read it the same way each time and then empty it. A figure of 6 mm is useless the next day if both days are still in the cone, or if you measured the top of the water one morning and the bottom the next. This routine is for a manual garden gauge you already own. It is not the Met Office method for a five-inch storage gauge, and it will not make a plastic cone agree with the town total. Models, if you still need one, are on the [rain gauge comparison](/hub/climate-measuring/rain-gauge).
The tube in the border becomes a record only when you read it the same way each time and then empty it.
The tube in the border becomes a record only when you read it the same way each time and then empty it. A figure of 6 mm is useless the next day if both days are still in the cone, or if you measured the top of the water one morning and the bottom the next. This routine is for a manual garden gauge you already own. It is not the Met Office method for a five-inch storage gauge, and it will not make a plastic cone agree with the town total. Models, if you still need one, are on the rain gauge comparison.
Our top picks
| Badge | Product | Scale | Reading aid | How you empty it | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  TFA Dostmann TFA Dostmann 47.1001 rain gauge | Unit not stated | Memory ring | Pour it out | 9.1 | about £8.72 | View offer |
 Tildenet Tildenet T22 rain gauge | Millimetres and inches | Magnified cone | Pour it out | 9.3 | about £8.97 | View offer | |
| Alternative |  CKB LTD CKB LTD 100 cm rain gauge | Inches and millimetres | Yellow float | Lift it out | 7.2 | about £33.95 | View offer |
On this page
Read the scale that is printed, not a ruler
Water climbs the wall of a tube, so the surface is a curve. You read the bottom of that curve, with your eye level with the mark, not the higher edge where the water touches the plastic. On a float gauge, such as the yellow disk on the CKB LTD 100 cm model, you read the float against the printed scale.
A magnified cone catches people. On the Tildenet, reviewers say under 0.5 mm is hard to read. One CKB 100 cm reviewer found the spacing wider than a millimetre. That is a reason to doubt the printing, not to invent a correction. A UK forecast is in millimetres. An inches-only tube, such as the CKB 75 cm listing up to 7 inches, is consistent only if your note says inches.
Same time each day, then write it down
The Met Office reads a storage gauge at 0900 UTC and pours it out. Your cone can borrow the habit without borrowing the claim. A reading at 8am on Monday and 6pm on Tuesday mixes two stretches of weather, so those looks are not a daily series.
Write the date, the time, the unit and the depth. If a chart came with the Tildenet or the STOWBERRY, fill the line while you are standing there. The TFA Dostmann 47.1001 memory ring marks the level you have just read. One reviewer says the ring is loose, so it is a marker, not a lock. If the cone is empty and the road is wet, check the site on where to put a rain gauge.
Empty it before the next shower
A manual gauge stores every drop until you pour it out. Empty it after you write the number, including trace days.
If the tube is full, write overflow at 7 inches on the CKB 75 cm gauge, or full where the listing states no capacity. There is no honest way to reconstruct what spilled. The CKB 100 cm gauge is emptied by lifting it out, and the listing does not describe a drain. A STOWBERRY review mentions the level falling while the water sits. UKHSA guidance on standing water applies to a gauge left full through a warm week. Pour it on the border. The Geevon claims to empty itself, so you cannot re-check that water. That exception is on manual or wireless rain gauge.
Snow and a frozen tube are not a rainfall total
Snow in the mouth is not a rainfall depth. A cap of snow will melt later and look like rain at the wrong time. Ice can split the plastic. A KINGLAKE-style gauge cracked when water froze inside it, and a Thermometer World buyer replaced one that failed in a Devon winter. The ACTIMED title says freeze proof, without a freeze test in the sampled UK reviews. If frost is forecast, empty the manual gauge after the morning read.
Common questions
Where on the water line do I read?
Read the bottom of the curve, with your eye level with the mark. The edge where the water clings to the plastic sits higher and will inflate the depth if you use it one day and not the next. On a float gauge, read the float against the printed scale. On a magnified cone such as the Tildenet, use the printed marks only. A ruler along the column measures the plastic.
Do I empty it every day?
Yes, after you record it, on every day you treat the tube as a daily gauge. Water left in the cone adds to the next shower and can evaporate or freeze. Empty it on trace days too. The Geevon is the exception only because it claims to empty itself. A tall manual gauge such as the CKB 100 cm model still has to be emptied by lifting it.
What if it overflowed?
Record that the gauge reached the top of the scale, and name the maximum if the listing states one, such as 7 inches on the CKB 75 cm gauge. Then empty it. You know at least that much rain fell. You do not know the surplus, and you should not estimate it. The next shower needs an empty tube.
Why do the marks look too far apart?
On a magnified cone the lower marks are stretched so a small fall is easier to see. Read them, and accept that under 0.5 mm may still be unclear on a Tildenet. If the gaps look nothing like the unit promised, which is what a CKB 100 cm reviewer described, the printing is the problem. Do not convert the gap with a ruler and call the result millimetres.
What about snow or a frozen tube?
Snow in the mouth is not a rainfall total, and ice in the tube is not a reading. Empty a manual gauge before a frost if you can, because frozen water can crack the plastic, as reviewers have found. Do not stir snow into the cone and log the melt as that day's rain. This set does not give you a tested frost-proof station for a gauge you leave out all winter.
Related pages
Sources
Public UK sources and the amazon.co.uk listings saved for this comparison. Pages were read on 19 October 2026.
- Met Office — How we measure rainfall (retrieved 19 October 2026)
- Met Office WOW — Site ratings (retrieved 19 October 2026)
- CEDA — Rainfall gauge catch comparison (retrieved 19 October 2026)
- RHS — Watering (retrieved 19 October 2026)
- GOV.UK — Check for flooding (retrieved 19 October 2026)
- UKHSA — Invasive mosquitoes and standing water (retrieved 19 October 2026)
- Consumer Rights Act 2015 (retrieved 19 October 2026)
- amazon.co.uk — Best sellers in rain gauges (retrieved 19 October 2026)