Every heat event the pipeline tracked between 2023-05-01 and 2023-09-30, with how each one grew, peaked and moved. Anomalies are against the 1991–2020 baseline.
Season at a glance
Events tracked
27
Total heat burden
115.47 Mkm²·days
Longest
29days (#6)
Hottest
+17.0°C (#5)
With a heat dome
11of 27 events
A heat dome is the stricter object: a tracked heat event with a closed 500 hPa anticyclone whose influence cap overlies it, after Loikith et al. (2026). Most heatwaves are not domes, so the label is a finding and not a synonym.
ERA5 daily maximum 2 m temperature over land, against the 1991–2020 climatology (p90 in a centred 15-day window). A heatwave cell is Tx above p90 on at least 3 consecutive days.
When the events ran
Overlapping bars are concurrent events in different places, not one event counted twice: each is a separately labelled cluster of contiguous heatwave cells.
How each event evolved
Event #26 — 2023-09-17 → 2023-09-30 14 daysheat dome · 13/14 d · Z500 +286 m
peak 2.63 M km² on 2023-09-28 · max +13.1 °C · mean +8.8 °C · burden 21.00 M km²·d · drift 483 km (54.0 N 24.8 E → 49.7 N 25.0 E)
Event #20 — 2023-08-09 → 2023-08-31 23 dayshigh on 10/23 d only
peak 2.06 M km² on 2023-08-21 · max +14.9 °C · mean +7.6 °C · burden 19.25 M km²·d · drift 2258 km (43.6 N 3.3 E → 51.3 N 31.4 E)
Event #22 — 2023-09-02 → 2023-09-15 14 daysheat dome · 8/14 d · Z500 +283 m
peak 2.31 M km² on 2023-09-11 · max +14.0 °C · mean +8.2 °C · burden 17.57 M km²·d · drift 1729 km (47.9 N 3.8 E → 43.4 N 25.2 E)
Event #13 — 2023-07-07 → 2023-07-27 21 daysheat dome · 13/21 d · Z500 +209 m
peak 707k km² on 2023-07-19 · max +13.6 °C · mean +6.3 °C · burden 9.18 M km²·d · drift 2006 km (48.8 N 7.7 E → 37.1 N 26.6 E)
Event #16 — 2023-08-02 → 2023-08-27 26 dayshigh on 5/26 d only
peak 836k km² on 2023-08-13 · max +12.6 °C · mean +6.2 °C · burden 9.10 M km²·d · drift 395 km (41.9 N 26.9 E → 39.3 N 30.1 E)
Event #8 — 2023-06-09 → 2023-07-01 23 daysheat dome · 12/23 d · Z500 +231 m
peak 782k km² on 2023-06-17 · max +14.0 °C · mean +8.1 °C · burden 8.07 M km²·d · drift 1074 km (59.2 N 5.8 E → 67.7 N 16.1 E)
Event #6 — 2023-05-26 → 2023-06-23 29 dayshigh on 5/29 d only
peak 519k km² on 2023-06-20 · max +12.9 °C · mean +7.1 °C · burden 5.01 M km²·d · drift 1474 km (46.4 N -1.4 E → 45.4 N 17.6 E)
Event #17 — 2023-08-03 → 2023-08-17 15 daysheat dome · 13/15 d · Z500 +342 m
peak 503k km² on 2023-08-07 · max +13.7 °C · mean +7.7 °C · burden 3.40 M km²·d · drift 1055 km (55.5 N 38.0 E → 64.6 N 43.2 E)
Event #12 — 2023-07-06 → 2023-07-26 21 daysheat dome · 12/21 d · Z500 +167 m
peak 236k km² on 2023-07-10 · max +15.1 °C · mean +6.6 °C · burden 3.30 M km²·d · drift 131 km (36.1 N 7.3 E → 35.3 N 6.3 E)
Event #4 — 2023-05-19 → 2023-05-25 7 dayshigh on 3/7 d only
peak 417k km² on 2023-05-21 · max +16.5 °C · mean +10.1 °C · burden 1.80 M km²·d · drift 438 km (69.3 N 27.3 E → 67.5 N 37.0 E)
Event #7 — 2023-06-02 → 2023-06-19 18 daysheat dome · 11/18 d · Z500 +231 m
peak 219k km² on 2023-06-13 · max +11.9 °C · mean +7.4 °C · burden 1.78 M km²·d · drift 165 km (56.7 N -4.3 E → 55.9 N -2.0 E)
Event #18 — 2023-08-04 → 2023-08-14 11 dayshigh on 3/11 d only
peak 296k km² on 2023-08-08 · max +14.4 °C · mean +6.2 °C · burden 1.76 M km²·d · drift 653 km (37.7 N -8.6 E → 41.3 N -2.5 E)
Event #21 — 2023-08-30 → 2023-09-04 6 dayshigh on 3/6 d only
peak 419k km² on 2023-09-02 · max +12.4 °C · mean +8.1 °C · burden 1.51 M km²·d · drift 454 km (61.6 N 35.7 E → 64.8 N 41.5 E)
Event #1 — 2023-05-01 → 2023-05-11 11 daysheat dome · 6/10 d · Z500 +212 m
peak 315k km² on 2023-05-03 · max +13.7 °C · mean +8.0 °C · burden 1.50 M km²·d · drift 294 km (39.9 N -5.0 E → 37.3 N -5.6 E)
Event #11 — 2023-07-03 → 2023-07-08 6 dayshigh on 3/6 d only
peak 457k km² on 2023-07-06 · max +10.2 °C · mean +6.5 °C · burden 1.49 M km²·d · drift 552 km (44.4 N 40.1 E → 48.7 N 43.8 E)
Event #2 — 2023-05-08 → 2023-05-18 11 dayshigh on 5/11 d only
peak 355k km² on 2023-05-15 · max +15.8 °C · mean +9.8 °C · burden 1.47 M km²·d · drift 862 km (65.8 N 20.7 E → 67.6 N 39.9 E)
Event #23 — 2023-09-02 → 2023-09-10 9 daysheat dome · 7/9 d · Z500 +283 m
peak 218k km² on 2023-09-08 · max +12.9 °C · mean +7.9 °C · burden 1.43 M km²·d · drift 521 km (57.5 N -2.9 E → 52.9 N -1.3 E)
Event #9 — 2023-06-14 → 2023-06-24 11 dayshigh on 1/11 d only
peak 272k km² on 2023-06-17 · max +9.9 °C · mean +7.0 °C · burden 1.40 M km²·d · drift 244 km (58.2 N 28.9 E → 56.0 N 28.3 E)
Event #19 — 2023-08-07 → 2023-08-17 11 daysheat dome · 8/11 d · Z500 +342 m
peak 282k km² on 2023-08-10 · max +14.7 °C · mean +8.3 °C · burden 1.39 M km²·d · drift 438 km (70.1 N 30.2 E → 67.3 N 37.8 E)
Event #10 — 2023-06-23 → 2023-06-29 7 dayshigh on 1/7 d only
peak 178k km² on 2023-06-26 · max +11.7 °C · mean +6.9 °C · burden 858k km²·d · drift 269 km (38.2 N -7.4 E → 38.1 N -4.3 E)
Event #3 — 2023-05-14 → 2023-05-18 5 dayshigh on 2/5 d only
peak 209k km² on 2023-05-16 · max +14.8 °C · mean +10.4 °C · burden 633k km²·d · drift 369 km (64.6 N 38.7 E → 61.8 N 42.5 E)
Event #15 — 2023-07-16 → 2023-07-21 6 dayshigh on 2/6 d only
peak 187k km² on 2023-07-18 · max +10.2 °C · mean +5.5 °C · burden 571k km²·d · drift 104 km (37.7 N -3.2 E → 37.5 N -2.0 E)
Event #25 — 2023-09-15 → 2023-09-22 8 dayshigh on 3/8 d only
peak 113k km² on 2023-09-17 · max +12.2 °C · mean +6.5 °C · burden 535k km²·d · drift 256 km (36.4 N 7.3 E → 35.5 N 9.9 E)
Event #5 — 2023-05-20 → 2023-05-26 7 dayshigh on 2/7 d only
peak 103k km² on 2023-05-22 · max +17.0 °C · mean +10.7 °C · burden 453k km²·d · drift 10 km (68.5 N 45.0 E → 68.5 N 44.8 E)
Event #14 — 2023-07-10 → 2023-07-14 5 daysheat dome · 3/5 d · Z500 +152 m
peak 122k km² on 2023-07-12 · max +13.1 °C · mean +8.3 °C · burden 413k km²·d · drift 219 km (68.6 N 22.0 E → 70.2 N 25.4 E)
Event #27 — 2023-09-20 → 2023-09-23 4 daysno overlying high
peak 139k km² on 2023-09-21 · max +11.0 °C · mean +7.7 °C · burden 380k km²·d · drift 334 km (47.0 N 18.0 E → 44.4 N 20.1 E)
Event #24 — 2023-09-04 → 2023-09-07 4 daysno overlying high
peak 101k km² on 2023-09-06 · max +7.7 °C · mean +5.6 °C · burden 196k km²·d · drift 46 km (38.8 N 44.5 E → 39.0 N 44.1 E)
Filled area is the event footprint in km² (left axis); the solid line is the peak anomaly inside it and the dashed line the mean (right axis). The small panel is the centroid path, circles sized by area and the ring marking day one. Drift is the straight-line start-to-end distance, so a dome that wandered and returned reports a small number.