Midsummer 2026 in Sweden: updated observations

Data downloaded 8 September 2026

Swedish temperature record dashboard

The 2026 observations are now included. For 15 June–15 July, 28 locations provide all 31 paired daily Tmax/Tmin values. Stockholm is absent because the configured series ends in March 2024.

How warm was the 31-day window?

In a fixed network of 18 stations with complete paired windows every year from 1961 through 2026, the 2026 temperature-mean proxy is 17.255 °C, ranking 7th warmest of 66 years. The ranking is seventh in both the merged input and adjusted series. 2021 has the highest window mean in this comparison.

The mean across all 28 available locations in 2026 is 16.947 °C. Its different value reflects a different station set. Neither number is an area-weighted national temperature. The proxy (Tmax+Tmin)/2(T_{\max}+T_{\min})/2 is not SMHI’s official daily mean calculation.

Fixed-network comparison and coverage.

A warm window is not the same as a heatwave

A 31-day average can conceal a short intense episode. The separate summer diagnostic below uses at least three consecutive June–August days above a monthly 95th percentile from 1991–2020, requires at least 95% summer coverage, and lets missing days break spells. Tmax measures hot-day spells; Tmin measures warm-night spells. Thresholds are estimated separately within each treatment. This is an illustrative study definition, not an official warning criterion.

variable name valid_summer_days events event_days longest_spell threshold_exceedance_days
tmax Karlshamn 92 1 7 7 10
tmax Kalmar 92 1 7 7 12
tmax Lund 92 1 4 4 11
tmax Växjö 92 2 7 4 10
tmax Jönköping 92 2 7 4 10
tmax Visby 92 1 4 4 7
tmax Vänersborg 92 2 7 4 12
tmax Västerås 92 2 7 4 11
tmax Göteborg A 92 1 3 3 6
tmax Borås 92 1 3 3 7
tmax Gladhammar A 92 1 3 3 9
tmax Skara 92 2 6 3 8
tmax Malmslätt 92 2 6 3 10
tmax Karlstad 92 1 3 3 5
tmax Örebro 92 2 6 3 7
tmax Uppsala 92 2 6 3 8
tmax Falun 92 1 3 3 6
tmax Sveg 92 1 3 3 4
tmax Härnösand 92 1 3 3 5
tmax Halmstad 92 0 0 0 2
tmax Gävle 92 0 0 0 6
tmax Delsbo 92 0 0 0 4
tmax Frösön 92 0 0 0 1
tmax Umeå 92 0 0 0 2
tmax Piteå 92 0 0 0 2
tmax Haparanda 92 0 0 0 1
tmax Jokkmokk 92 0 0 0 0
tmax Karesuando 92 0 0 0 0
tmin Örebro 92 1 6 6 9
tmin Gladhammar A 92 1 5 5 8
tmin Visby 92 1 5 5 10
tmin Malmslätt 92 1 5 5 10
tmin Göteborg A 92 1 4 4 11
tmin Lund 92 1 3 3 7
tmin Borås 92 1 3 3 5
tmin Vänersborg 92 1 3 3 8
tmin Skara 92 1 3 3 7
tmin Uppsala 92 1 3 3 9
tmin Falun 92 1 3 3 8
tmin Delsbo 92 1 3 3 5
tmin Karesuando 92 1 3 3 8
tmin Halmstad 92 0 0 0 7
tmin Karlshamn 92 0 0 0 5
tmin Växjö 92 0 0 0 6
tmin Kalmar 92 0 0 0 3
tmin Jönköping 92 0 0 0 10
tmin Karlstad 92 0 0 0 5
tmin Västerås 92 0 0 0 8
tmin Gävle 92 0 0 0 5
tmin Sveg 92 0 0 0 3
tmin Härnösand 92 0 0 0 3
tmin Frösön 92 0 0 0 1
tmin Umeå 92 0 0 0 3
tmin Piteå 92 0 0 0 2
tmin Haparanda 92 0 0 0 1
tmin Jokkmokk 92 0 0 0 2

What can be concluded?

The observed 2026 window is among the warmer windows in the fixed-network comparison. Its empirical rank is not a return period, evidence that a particular episode was a record, or an attribution to a particular climate scenario.

The daily adjustments were fitted only through 2025 and then applied to 2026. The method’s earlier benchmark tests exposed seasonal, scale and tail failures. It still introduces 1,275 additional Tmin-above-Tmax pairs in the refreshed 1884–2025 history. The recent SMHI feed retains quality flags; aggregated or less fully checked values need explicit treatment in any event inference. These limitations remain despite adding the new observations.

Source: SMHI daily observations. The previous dataset, reports and original downloads remain archived. Updated 8 September 2026.