Why the Ratio of Record Highs to Record Lows Matters

In a stable climate a station would set about as many record highs as record lows over a long period, so the ratio between them would sit near one to one. That is why the ratio tells you more than either count: it removes most of what makes raw counts hard to compare.

Why not just count records

The number of records set in a year depends on how many stations are reporting and how long they have been running. Both change over time. A ratio removes most of that, because the same stations and the same rules produce both counts.

Take the current year. As of 12 October 2026 the ledger shows 138,705 record highs and 26,597 record lows so far this year, a ratio of 5.2 to 1. Neither number means much alone. Ten thousand records could be a busy year or a large network. The ratio is the same either way.

What a steady climate would give

Records are easiest to set early in a station’s history, when the record is only a few years old. So even with no trend, the count of records falls over time, for highs and lows alike. That effect hits both sides equally, which is the second reason to use the ratio. If highs and lows are equally likely, the ratio stays near one however long the stations have run.

What the long series shows

Our world series starts in 1897, when the ratio was 1.8 to 1. The latest full year on file, 2026, stands at 5.2 to 1. By decade the ratio moves from 1.1 to 1 in the 1900s to 3.2 to 1 in the 2020s. You can see every year and every country on the ratio page.

What the ratio does not say

A ratio above one to one does not tell you how big the change is at any place, and a single year can be noisy. Stations are not spread evenly over the world, so the world ratio leans toward regions with dense networks. Read it as a trend over decades, and read it next to the methodology so you know what is being counted. Our explainer on what a weather record is covers the definitions, and how we count records covers the rules.

How to use it

Compare like with like: the same scope, the same window, ideally a decade or more. Be wary of any headline that quotes only highs or only lows. The ratio page gives both, with the year to date beside the previous ten years for the same days.