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This might be complicated to resolve:

• July 1757: Experienced an average monthly temperature of \(25\phantom{\,}^{\circ}\text{C}\) (\(77\phantom{\,}^{\circ}\text{F}\)), with a recorded high of \(37.5\phantom{\,}^{\circ}\text{C}\) (\(99.5\phantom{\,}^{\circ}\text{F}\)) on July 14.

"July 1757 was extraordinarily hot in Paris, and it was much closer to July 2026 than my previous answer implied.

For July 2026 at Paris-Montsouris, the observed average daily maximum was 30.8°C and average minimum 18.5°C. Simply averaging those gives about 24.6°C as a rough monthly mean. The hottest day was 29 July at 38.3°C. Paris had 15 days ≥30°C, 6 days ≥35°C, and 10 tropical nights ≥20°C.  

The historical Paris series gives July 1757 a monthly mean of about 25.0°C, with an average maximum of 29.9°C and minimum of 20.1°C. That makes it, remarkably, roughly comparable to or possibly slightly hotter than July 2026 by the historical series’ monthly-mean calculation. Météo-France confirms that Paris has genuine instrumental temperature records extending back into this period, although the observing methods and locations differ from modern Montsouris measurements.  

And the actual 1757 heatwave was bonkers:

Date

1757 min / max

2026 min / max

Jul 9

20.0 / 31.9°C

22.5 / 34.3°C

Jul 10

21.3 / 33.8

21.8 / 36.0

Jul 11

24.4 / 35.0

22.3 / 36.7

Jul 12

22.5 / 35.6

22.0 / 36.5

Jul 13

23.8 / 35.0

22.4 / 35.8

Jul 14

25.0 / 37.5

20.8 / 35.0

Jul 15

21.3 / 31.9

23.6 / 32.7

Jul 16

22.5 / 26.3

21.2 / 33.9

Jul 17

21.3 / 29.4

19.7 / 28.7

Jul 18

20.6 / 31.3

18.8 / 29.8

Jul 19

18.8 / 33.8

15.2 / 25.2

Jul 20

23.1 / 37.5

13.5 / 24.8

1757 data:   2026 data:  

That comparison changes the picture dramatically. July 2026 generally had hotter afternoons during the core July 9–16 stretch, but 1757 often had warmer nights and then absolutely demolished 2026 after July 16. July 20 is the wildest contrast: 37.5°C in 1757 versus only 24.8°C in 2026.

The single hottest readings are also almost tied: 37.5°C on July 14 and again July 20, 1757, versus 38.3°C on July 29, 2026. So 2026 wins the absolute maximum by only 0.8°C.  

There is an important historical-instrument caveat. A 25.0°C monthly mean in 1757 is not perfectly apples-to-apples with a modern Montsouris mean because thermometers, exposure, observation times, station locations, and homogenization all matter. Météo-France describes the old Paris series as assembled from early instrumental observations and later linked to the Montsouris series.  

So the defensible answer is:

1757 ≈ 2026 for the whole July, with 1757 plausibly slightly hotter according to the historical Paris series.

Not 2026 hotter by 4–6°C. That earlier estimate was wrong.

And there is an extra bit of climate weirdness here: France as a whole had its hottest month in the modern national record in July 2026, averaging 24.9°C, yet Paris’s legendary 1757 local July still manages to go toe-to-toe with it.  

1757 was not merely “warm for the Little Ice Age.” It was a meteorological flamethrower. 🔥"