Warm June Nights: What Six Station Series Can Tell Us

EuroMeteo
WMO Normals
Extreme Weather
Six June 2026 station series contain high minimum reports, but missing hours can hide cooler readings. Compare temperatures, WMO normals and coverage.
Author

Climate Explorer Team

Published

June 30, 2026

Modified

September 13, 2026

At Paris-Montsouris, the lowest available temperature report on June 25, 2026 was 26.4°C. That is a warm reading even for the coolest reported part of a day. Five other European station series also contained days whose lowest report was above 20°C.

But an archive of hourly reports does not necessarily capture the true daily minimum. Missing hours can hide cooler temperatures. Madrid’s highest minimum report, 25.9°C on June 12, comes from just 14 represented hours. It should not be presented as proof that the temperature stayed that high through a whole night.

Paris-Montsouris lowest available June temperatures, with open circles for days missing one or more UTC hours.

Paris has reports on all 30 June dates, with 22–24 different hours represented per date. The June 25 value has all 24 hours represented. Even hourly coverage can miss an extreme between reports.

A warm report and a tropical-night classification are different checks

The familiar 20°C (68°F) tropical-night reference is useful when reading these series. Applying a formal classification also requires the relevant observing window and a sufficiently complete minimum-temperature record.

Here, each point is the smallest valid air_temperature value available between 00:00 and 23:59 UTC. Those boundaries need not match a national daily product or one local night. The figure therefore labels the values as lowest reports, rather than official tropical-night minima.

A filled marker means at least one report exists in every UTC hour. An open marker means one or more hours are absent. Neither symbol certifies continuous measurement, a final provider quality status or equal sampling frequency between stations. Multiple streams can supply reports within an hour.

Coverage changes the reading of Madrid

Madrid has 29 observed June dates in the retained feed; June 11 is absent. June 12 has only 14 represented hours, and the least-covered Madrid date has 11. The chart leaves the missing date as a gap. Joining a line across it would suggest continuity the data do not provide.

Madrid recorded the same lowest report, 25.9°C, on June 24, with all 24 hours represented. The equal values therefore have different observational support; both dates are retained in the table.

For comparison, the highest minimum reports at Vienna, Budapest, Warsaw and Paris each have observations in all 24 hours. Berlin’s June 28 value has 23. The table below keeps that coverage beside the temperature, so the six peak values do not look equally well observed.

The other five series

Madrid-Retiro

Madrid-Retiro lowest available temperatures during June. Filled points have reports in all 24 hours; open points have gaps. The 20°C reference and 16.5°C June normal are marked.

29 June days have observations; the least-covered day has reports in 11 different UTC hours. Open circles identify days with fewer than 24 hours represented.

Berlin-Tempelhof

Berlin-Tempelhof lowest available temperatures during June. Filled points have reports in all 24 hours; open points have gaps. The 20°C reference and 12.8°C June normal are marked.

30 June days have observations; the least-covered day has reports in 19 different UTC hours. Open circles identify days with fewer than 24 hours represented.

Vienna-Hohe Warte

Vienna-Hohe Warte lowest available temperatures during June. Filled points have reports in all 24 hours; open points have gaps. The 20°C reference and 14.7°C June normal are marked.

30 June days have observations; the least-covered day has reports in 22 different UTC hours. Open circles identify days with fewer than 24 hours represented.

Budapest-Pestszentlőrinc

Budapest-Pestszentlőrinc lowest available temperatures during June. Filled points have reports in all 24 hours; open points have gaps. The 20°C reference and 15.2°C June normal are marked.

30 June days have observations; the least-covered day has reports in 22 different UTC hours. Open circles identify days with fewer than 24 hours represented.

Warsaw-Okęcie

Warsaw-Okęcie lowest available temperatures during June. Filled points have reports in all 24 hours; open points have gaps. The 20°C reference and 12.4°C June normal are marked.

30 June days have observations; the least-covered day has reports in 22 different UTC hours. Open circles identify days with fewer than 24 hours represented.

Use the normal as context

The dotted lines are 1991–2020 WMO June mean daily minimum temperatures. They describe an average June minimum at each station, not a calendar-day expectation or an extreme threshold. Subtracting one from a single day’s lowest report supplies context, but the sampling limits remain.

The station identifiers matter too. These are individual sites—Retiro, Tempelhof and Okęcie, for example—not average temperatures across their respective cities. The EuroMeteo guide explains how to inspect station observations; the WMO normals explainer explains the reference statistics.

Conclusion

Observational series from six European capitals reveal widespread, pronounced nocturnal heat during late June 2026, with lowest available daily reports sitting 8°C to nearly 13°C above 1991–2020 WMO June mean minimum baselines. Paris-Montsouris reached an elevated minimum report of 26.4°C on 25 June, while Berlin-Tempelhof and Warsaw-Okęcie each reported minimums near 25°C late in the month. Crucially, examining report coverage alongside raw values shows that operational point feeds with missing hours cannot definitively confirm a climatological tropical night, as unobserved cooler periods may have occurred. Distinguishing raw interim reports from validated 24-hour minimums is necessary for accurate climatological interpretation.

Editor’s note: Data current as of June 30, 2026. Hourly observations, coverage totals and WMO 1991–2020 station baselines were rechecked against E-SOH parquet archives on September 13, 2026. Upstream feeds remain subject to subsequent quality control by national providers.

Frequently Asked Questions

Does a minimum report above 20°C prove a tropical night?

No. Missing or infrequent reports may omit cooler temperatures, and UTC calendar days may differ from the observing window used for an official tropical-night classification.

Does a filled circle mean there are no data gaps?

It means each of the 24 UTC hours contains at least one report. It does not mean that every minute was observed or that the true daily minimum was captured.

Data Annex

Station metadata

Station metadata
Station Observation WIGOS ID WMO normals ID Latitude Longitude Elevation
Paris-Montsouris 0-250-0-07156 07156 48.8217° N 2.3378° E 75 m
Madrid-Retiro 0-20000-0-08222 08222 40.4118° N 3.6781° W 667 m
Berlin-Tempelhof 0-20000-0-10384 10384 52.4676° N 13.4020° E 47.7 m
Vienna-Hohe Warte 0-20000-0-11035 11035 48.2486° N 16.3564° E 198 m
Budapest-Pestszentlőrinc 0-348-1-44527 12843 47.4292° N 19.1822° E 138.1 m
Warsaw-Okęcie 0-20000-0-12375 12375 52.1667° N 20.9667° E 106.5 m

WIGOS IDs identify the observation-feed stations; the five-digit IDs identify the corresponding rows in the normals archive. Coordinates and elevations shown here come from the maintained observation metadata. The normals CSV stores a discrepant longitude for Warsaw-Okęcie, but its legacy ID and station name match the observation station.

A WIGOS ID is a globally unique station identifier. The baseline join preserves the separately verified legacy WMO ID; it does not derive station identity from a city name alone.

Highest minimum reports and their coverage

Highest available minimum report per station; the coverage column applies to that particular date
Station UTC date Lowest report (°C) Hours represented June normal (°C) Difference (°C)
Paris-Montsouris 2026-06-25 26.4 24 14.2 +12.2
Madrid-Retiro 2026-06-12 25.9 14 16.5 +9.4
Madrid-Retiro 2026-06-24 25.9 24 16.5 +9.4
Berlin-Tempelhof 2026-06-28 24.9 23 12.8 +12.1
Vienna-Hohe Warte 2026-06-29 23.8 24 14.7 +9.1
Budapest-Pestszentlőrinc 2026-06-29 23.2 24 15.2 +8.0
Warsaw-Okęcie 2026-06-29 25.0 24 12.4 +12.6

The calculation reads all 30 daily parquet files for June, explicitly filters timestamps to June 1–30 UTC and retains air_temperature between −50°C and 60°C. These broad plausibility bounds do not replace provider quality control. There are 179 station-days across the six sites. No absent day or hour is interpolated. Report counts and distinct represented hours are separate columns in the complete chart-ready CSV.

The six baseline values were re-extracted from the WMO normals composite on September 13, 2026. This revision rechecks the retained June observation snapshot; it does not claim that the live feed still contains exactly the same reports.

Data Sources