The spring index shows the long-term development of flowering and/or leaf unfolding! of nine different plant species that occur from January to May. The development of spring vegetation in 2023 was 3 days ahead of the average for the 30-year period 1991-2020 and can be classified as “normal” (Figure 1). However, compared to the average for the period 1961-1990, spring arrived almost 10 days earlier.
The temporal course of the spring index shows a sudden advancement starting around 1990.
Figure 1: The spring index shows the timing of vegetation development in days of deviation from the long-term average 1991-2020. In dark green are the years with later vegetati
on development than the average, in light green the years with earlier vegetation development. In yellow is the 5-year weighted average. (MeteoSwiss)
spring index and temperature
>The national average temperature for the months February to singapore phone number library April shows an increase of about 2 °C since 1960.
>Figure 2: Average temperature in Switzerland for the months February to April from 1954-2023 as a deviation from the average 1991-2020. (MeteoSwiss)
Earliest flowering of hazel bushes since observation began
This year, the hazel bushes bloomed earlier than ever since they began to be observed in 1953. The reason for this very early bloom was the long period of extremely mild temperatures from December 20th to January 15th. This meant that at the beginning of January, significantly more hazel bushes were blooming in all regions of Switzerland than in other years with a similarly early start to flowering but shorter warm periods. Since the excess heat in Ticino at the end of December was not quite as great as on the northern side of the Alps, for once the hazel blossom began slightly later in Ticino than on the northern side of the Alps. After January 15th, it became cool and it was not until mid-February that the hazel blossomed at higher altitudes. Across all observation stations, the hazel blossom was 23 days ahead of the average for the standard period 1991-2020.
The cool April slowed down the spring vegetation
The cherry trees began to bloom at the end of March simultaneously in Ticino and northwestern Switzerland. The cherry trees began to bloom widely from the first week of April, although the persistently cool how to handle objections in telephone sales temperatures slowed their blossoming. They therefore bloomed at a normal time, two days ahead of the average. The apple trees, which bloomed about two weeks later, bloomed exactly in line with the long-term average. Late frost damage to fruit trees was hardly a problem this spring.
In the meadows, dandelions and meadowfoam were already awb directory flowering more frequently at the end of March and beginning of April. Their flowering was therefore 4 – 7 days ahead of the average.
