Material from: Linus, Ivan


 

Discussed in the following Daily reports:



1. Overview

 

The late-June 2026 episode produced a remarkably broad cluster of national June maxima records across north-western, central and parts of southern Europe. The most striking feature is that several June records were not merely monthly records but new all-time national records: Germany, Czechia, Poland and Denmark, with Hungary possibly joining that category depending on final verification of the later 42.0°C report. 

Below is a list of the maximum temperature records for June that was broken during the heatwave:

Country / areaNew record reportedDate / stationWhat was broken
United Kingdom37.7°C26 June, Lingwood / Strumpshaw Hill, NorfolkUK/England June daily maximum record; previous UK June record was 35.6°C at Southampton in June 1976. The Met Office notes this was provisional. [metoffice.gov.uk]
Netherlands39.4°C26 June, Ell, LimburgNew national June temperature record; KNMI also issued an unprecedented red heat alert for parts of the country. [wmo.int], [nltimes.nl]
Switzerland39°CBaselNew Swiss June temperature record. [wmo.int]
Austria40.0°CVienna CityNew Austrian June temperature record. [wmo.int]
Germany41.7°C28 June, Coschen / Neißemünde-Coschen, BrandenburgNew German all-time maximum; since it occurred in June, it also supersedes the national June maximum. WMO notes Germany broke records on three consecutive days. [wmo.int], [dw.com]
Czech Republic / Czechia41.9°C28 June, DoksanyNew Czech all-time maximum; also a June maximum. CHMI was cited as saying this was the first time 41°C had been registered in the official network. [brnodaily.com], [nampa.org]
Poland40.5°C29 June reporting for SłubiceNew Polish all-time maximum; also a June maximum. The previous all-time record was 40.2°C from 1921; Słubice had already broken the June record the day before with 38.9°C. [polskieradio.pl]
Denmark37.0°CTwo locations, late JuneNew Danish all-time maximum, breaking a record from 1975; therefore also a June maximum. [wmo.int]
Hungaryat least 40.7°C28 June, near BudapestWMO reported a new Hungarian June temperature record of 40.7°C, with further intensification forecast. Later reporting also mentioned 42.0°C at Szécsény on 30 June, but the WMO snapshot I found only explicitly supports the 40.7°C June-record value.

2. Analyses and Observations

2.1 Event Definition

For this long-lived and widespread event is it difficult to define a specific time-window and location.

2.2 Analyses


2.3 Observations


2.4 Climatological perspective

The plot below show the evolution of the heatwave  in terms of daily mean anomalies. Locations where observed values exceeded the 99th percentile of the observed 20-year climate are also indicated.

3. Forecasts

3.1 Data assimilation and observation usage

 

3.2 Single Forecasts for the event based on 00UTC forecasts (defined in Section 2.1)

Observations and analysis for the event

Control forecast (IFS 9-km resolution)

DestinE (IFS 4.4km resolution)

AIFS-single (AIFSv1.0 ~0.25 resolution)

AIFS-CRPS ensemble (~0.25 degree resolution)

3.3 Ensemble distribution

EFI (based on IFS 9-km ensemble)

The plots below show the 3-day EFI for 2-metre temperature valid 23-25 June.

The plot below shows the evolution of 3-day mean temperature for Angers (0.5x0.5 degree box centred on 47.5N, 0.6W)  in western France valid 23-25 June.


Forecast Evolution plot

3.4 Sub-seasonal forecasts

 The maps below shows the verification plots for weekly 2-metre temperature anomalies for the week 22-29 June.

3.5 Comparison with other centres


4. Hazard Forecasts


5. Dedicated Experiments


6. Event Summary

6.1 Good and bad aspects of the forecasts for the event


6.2 Experience from general performance/other cases


7. Additional material