Global Extreme Weather and Climate Change Dashboard
Cold Extremes
Extreme temperatures -- heat and cold combined -- account for about 2% of global weather/climate economic losses but about 21% of deaths, 1980-2025 (see Loss Normalization), a disproportionate human toll relative to the direct dollar cost. This page is the cold-side counterpart to Heat Waves, built from the same GHCN-Daily GSN station network: four ETCCDI/CLIMDEX cold-side indices (TNn, CSDI, TN10p, Frost Days), sharing the 1949 reliable trend window Heat Waves' station count supports.
Summary Judgment
3 of 4 cold-extreme metrics (CSDI, TN10p, Frost Days) show a detected decrease since 1949, matching AR6's "less frequent and less severe" finding directly; the 4th (TNn) shows the same direction but doesn't clear the magnitude bar.
IPCC finding (AR6 WG1 SPM A.3.1): "...cold extremes (including cold waves) have become less frequent and less severe [across most land regions since the 1950s], with high confidence that human-induced climate change is the main driver of these changes." — see the full Detection & Attribution comparison for every phenomenon this site tracks.
Variables on this page
Every variable below is evaluated over a full reliable-trend window against the combined "detected change" standard (IPCC's likelihood criterion plus a magnitude-vs-variability check -- see the homepage or Methodology for the full definitions). Shown as alternative ways of characterizing this same phenomenon -- some from independent sources, others a different construction on the same underlying data (each variable's note says which).
Cold Extremes — TNn (Annual Min Temperature)
AnnualIPCC AR6/ETCCDI standard TNn -- the single coldest overnight low observed each year, no percentile threshold involved. The direct cold-side structural analog of the Heat Waves page's TXx. Unit: °C (annual min daily low).
Source: NOAA GHCN-Daily, GCOS Surface Network (GSN) stations
Computing trend…
Reports the single coldest overnight low observed each year, averaged across qualifying stations. See Methodology for validation against the February 2021 Winter Storm Uri cold wave.
Cold Extremes — CSDI (Cold Spell Duration Index)
AnnualETCCDI/CLIMDEX standard CSDI -- annual count of days in a run of 6+ consecutive days with an overnight low below a station's fixed-base-period (1961-1990) 10th percentile. The direct cold-side analog of the Heat Waves page's WSDI. Unit: days per year.
Source: NOAA GHCN-Daily, GCOS Surface Network (GSN) stations
Computing trend…
Counts days in a run of 6 or more consecutive days below each station's 1961-1990 base-period 10th percentile. See Methodology for the ETCCDI/CLIMDEX definition and validation against Winter Storm Uri.
Cold Extremes — TN10p (Cold Nights)
AnnualETCCDI/CLIMDEX standard TN10p -- percent of days with an overnight low below a station's fixed-base-period (1961-1990) 10th percentile. The direct cold-side analog of the Heat Waves page's TN90p. Unit: % of valid days.
Source: NOAA GHCN-Daily, GCOS Surface Network (GSN) stations
Computing trend…
Reports the percentage of days with an overnight low below each station's 1961-1990 base-period 10th percentile. See Methodology for the ETCCDI/CLIMDEX definition.
Cold Extremes — Frost Days
AnnualETCCDI standard Frost Days (FD0) -- annual count of days with an overnight low below 0°C. Unlike the other three cold-extreme panels, this is an absolute threshold, not relative to a station's history -- a directly actionable 'does the ground freeze' question. Unit: days per year.
Source: NOAA GHCN-Daily, GCOS Surface Network (GSN) stations
Computing trend…
Counts days with an overnight low below 0°C, an absolute threshold rather than a percentile-relative one. See Methodology for the ETCCDI standard definition.