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Konstanz sits 405 metres above sea level on the western shore of Lake Constance (Bodensee), where the lake’s 536 km² of water buffers the temperature year-round. Winters run milder than inland Baden-Württemberg and summers cooler than the Rhine valley, with lake water peaking around 22°C (72°F) in August. Expect roughly 834 mm of rain across about 124 wet days a year, with the wettest stretch running May through August. Use this Konstanz weather by month breakdown to pick your dates, then check the best time to visit Konstanz for season-by-season advice and the best neighborhoods in Konstanz to see which district suits each season.
Konstanz Weather by Month: January and February
January is the coldest month, with a daily high of 3.9°C (39°F) and an overnight low near -1.6°C (29°F), plus 45.8 mm of rain. Snow falls on about 6 days but rarely lingers in the city centre, and lake water sits around 4°C (39°F). February edges up to a 5.8°C (42°F) high with 44.8 mm, the driest month of the year. Bring a warm coat, gloves and waterproof shoes for the lakeside promenade, and book indoor sights like the Rosgartenmuseum on wet days.
Konstanz Weather by Month: March and April
March climbs to an 11.1°C (52°F) high with 50.6 mm of rain, and the first café terraces reopen on sunny afternoons. April reaches 16.0°C (61°F) with 56.5 mm, and this is when Insel Mainau’s tulip and spring-flower displays start pulling day-trippers. Overnight lows still hold between 1°C and 4°C (34-40°F), so keep a jacket for evenings and plan layers for the boat trips in our things to do in Konstanz guide.
Konstanz Weather by Month: May and June
May averages 20.3°C (69°F) by day with 89.2 mm, and lake water around 15°C (59°F) makes it the first plausible swimming month for hardy bathers. June reaches 23.9°C (75°F) with the year’s heaviest rainfall at 99.7 mm, often falling as short afternoon thunderstorms. Pack both sunscreen and a light rain shell, and note that early-season events like the Internationale Bodenseewoche regatta fall in late May and June.
Konstanz Weather by Month: July and August
July and August are the warmest months, with highs of 25.7°C (78°F) and 25.3°C (78°F) and lows near 14°C (57°F). Rainfall stays high at 96.3 mm and 97.7 mm, and lake water reaches its 22°C (72°F) peak, warm enough for the public swimming areas at Hörnle and Strandbad. Humidity runs 70-80%, so evenings can feel muggy. These are the busiest and priciest months for hotels; book early and see our where to stay in Konstanz pages before prices spike, and check the Konstanz travel tips for arrival details.
Konstanz Weather by Month: September and October
September cools to a 20.3°C (69°F) high with 69.4 mm, and the lake stays warm enough for swimming into early September at around 20°C (68°F). October drops to 14.6°C (58°F) with 62.8 mm and is a favourite for vineyard walks and clear autumn days with the Alps visible across the water. Mornings need a coat from mid-October, and the Zeltfestival fills late September.
Konstanz Weather by Month: November and December
November averages 8.2°C (47°F) with 57.5 mm, and grey, foggy days are common as the lake cools. December brings a 4.5°C (40°F) high with 63.2 mm, and the Christmas market opens in late November under lights strung across the Marktstätte. Snow is possible but intermittent, and lake ice is rare and usually unsafe. See the Konstanz events and festivals calendar for winter dates. For the full overview, see our Konstanz travel guide.
Konstanz Weather by Month: Monthly Averages at a Glance
| Month | Avg High | Avg Low | Rainfall |
|---|---|---|---|
| January | 3.9°C (39°F) | -1.6°C (29°F) | 45.8 mm |
| February | 5.8°C (42°F) | -1.4°C (29°F) | 44.8 mm |
| March | 11.1°C (52°F) | 1.0°C (34°F) | 50.6 mm |
| April | 16.0°C (61°F) | 4.4°C (40°F) | 56.5 mm |
| May | 20.3°C (69°F) | 8.7°C (48°F) | 89.2 mm |
| June | 23.9°C (75°F) | 12.3°C (54°F) | 99.7 mm |
| July | 25.7°C (78°F) | 14.1°C (57°F) | 96.3 mm |
| August | 25.3°C (78°F) | 13.7°C (57°F) | 97.7 mm |
| September | 20.3°C (69°F) | 9.8°C (50°F) | 69.4 mm |
| October | 14.6°C (58°F) | 6.0°C (43°F) | 62.8 mm |
| November | 8.2°C (47°F) | 2.2°C (36°F) | 57.5 mm |
| December | 4.5°C (40°F) | -0.5°C (31°F) | 63.2 mm |
