Editing Lake Constance (section)

=== Climate ===
[[File:Bodenseesturm.jpg|thumb|Summer storm – view of the [[Luitpoldkaserne (Lindau)|Luitpold Barracks]] in Lindau]]
The climate of the Lake Constance area is characterised by mild temperatures with moderate gradients, thanks to the balancing and retarding effect of the large body of water. 

It has a [[subtropical]] microclimate, which allows the cultivation of some exotic fruits and trees. Constance counts 2069 sunshine hours a year and is therefore considered one of the sunniest cities in Germany.

Winters are generally short and mild, although night temperatures can fall under 0°C, especially from December to February. Typically day temperatures range between +5 and +12°C, while nights with +1 to +8°C on average stay cold, though mostly without long and severe frosts.

The [[Föhn]], a warm wind from the [[Mediterranean Sea]], that regularly blows through the Alps, can cause temperatures between 15 and 20°C with sunshine for several days, while on the other hand fog creates a few cold days between 1 and 5°C each year. Generally, Lake Constance is affected more by fog than neighboring regions more inland. 

Spring goes from March to May and is usually sunny, with day temperatures between 15 and 22°C but still relatively cold water. This is also resulting in still cold night temperatures that range between 4°C in March and 12°C in May only. 

As the lake temperature heats up by the increasing warm days, the nights are also becoming milder, though moderated a little bit by the height and lake. This results in average morning lows of 16-18°C during the high summer months. Lake Constance counts one of the highest amount of [[tropical nights]] in Germany (lowest temperature at 20°C or more). 

The days in Summers (June-September) are warm to hot with day temperatures of 26-33°C on average, decreasing to around 20°C until the end of September. Humidity levels raise noticeable and temperatures often move up to 35°C between June and August. This increases the [[heat index]], causing Lake Constance to have a stressful climate.

The region receives most of its sunny days during high summer. In the recent years, in 2018 and 2022, the water levels fall to new record lows due to weeks without significant rain. On the other hand, the closeness to the Alps can cause thunderstorms in the evenings that sometimes occur out of nowhere.

While the official bathing season ends in September, the average lake temperature stays around 20°C until October. Autumn is generally the time when Lake Constance starts to experience more foggy mornings again, but the day temperatures still range between 21 in the beginning and 10-12°C at the end of the season. Night temperatures fall from 13°C in September to an average of 5°C in November.

Lake Constance is one of the best known wine growing regions in Germany and experiences several outdoor events during harvest time in autumn. 
 
[[File:Foehnwind am bodensee.jpg|thumb|left|Waves raised by Föhn winds]]
Lake Constance is also considered to be a risky and challenging lake for water sports because of the danger of gusty winds which can whip up waves as the weather changes suddenly. The most dangerous wind is the föhn, a warm down-slope wind from the Alps, which spreads out across the water, especially through the [[Alpine Rhine Valley]] and can generate waves several metres high.

Similarly dangerous for those unfamiliar with the area, are the sudden stormy gusts of wind during summer thunderstorms. They constantly claim victims from the water sports fraternity. During a thunderstorm in July 2006, waves reached heights of up to 3.50 metres.

For these reasons, there is a storm warning system in all three neighbouring countries. For [[storm warning]] purposes, Lake Constance is divided into three warning regions (west, centre and east). Warnings can be issued for each region independently. A "high winds" warning will be issued when [[squall]]s are expected of between 25 and 33&nbsp;[[knot (unit)|knots]] or registering [[wind speed|force]] 6 to 8 on the [[Beaufort scale]]. A [[gale warning]] announces the likelihood of gale-force winds, i.e. those at speeds as of 34 knots or more or force 8 on the Beaufort scale. In order to issue these warnings, orange-coloured flashing lights are installed around the lake, which flash at a frequency of 40 times per minute for high winds or 90 times per minute for gales. It can happen that, due to the differently regulated responsibilities and assessments, a gale warning is issued on the Swiss side of the Obersee, but not on the German or Austrian shores, and vice versa. Ships and ferries on Lake Constance indicate a gale warning by hoisting a ''Sturmballon'' ("storm ball") up the mast.

==== Freeze over ====
[[File:BodenseeGefroren.jpg|thumb|right|Frozen lake surface: skating in the [[Markelfinger Winkel]]]]
[[File:Seegfrörni 1963.jpg|thumb|right|Freezing of Lake Constance in 1963]]
A one-hundred year event is the freezing over of Lake Constance, when the Lower Lake and the Upper Lake are completely frozen over so that people can safely cross the lake on foot. The last so-called ''Seegfrörne'' ([[Alemannic German|Alemannic]]) event was in 1963. The following is a list of [[Anno Domini|years]] in which Lake Constance froze over partially or completely:<ref>{{cite book |last=Meichle |first=Friedrich |chapter=Seegfrörne und Eisprozession in Vergangenheit und Gegenwart |title=Schriften des Vereins zur Geschichte des Bodensees und seiner Umgebung |volume=81 |year=1963 |pages=145–170 |issn=0342-2070 |language=de}}</ref><ref>{{cite book |last=Dobras |first=Werner |title=Seegfrörne: die spannende Geschichte der Seegfrörnen von 875 bis heute. 2. veränderte Auflage |publisher=Stadler |location=Konstanz |year=1992 |isbn=3-7977-0266-3 |language=de}}</ref>

*875, 895
*1074, 1076
*1108
*1217, 1227, 1277
*1323, 1325, 1378, 1379, 1383
*1409, 1431, 1435 (complete), 1460, 1465, 1470, 1479
*1512, 1517, 1553, 1560 (complete), 1564, 1565, 1571, 1573 (complete)
*1684, 1695 (complete)
*1788, 1796 (complete)
*1830 (complete), 1880 (complete)
*1929, 1963 (complete)

Certain parts of the lake freeze over more frequently, mainly due to their shallow depth of water and shelter, as is the case, for example, of the so-called [[Markelfinger Winkel]] between the municipality of [[Markelfingen]] and the [[Mettnau]] peninsula.

==== Floods ====
* A [[100-year flood]] around June 1999 ([[Pfingsthochwasser 1999]]) raised the level about 2 metres above normal, flooding harbors and many shoreline buildings and hotels.
* In late August 2005, heavy rain raised the level by more than {{cvt|70|cm}} in a few days. The rains caused widespread flooding and washed out highways and railroads.
* Frequent rainfall and snowmelt in the summer of 2024 raised water levels to {{cvt|68|cm}} above normal level.

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[[File:Panorama Hochwasser im Rheinholz.jpg|center|600px|thumb|Flooding on the shore of Lake Constance, May 2013]]