Local changes

The extent of summer warming in the Alps is expected to be greater than in the other regions of Switzerland; at the same time, the increase in winter precipitation in that region is less pronounced. If greenhouse gas emissions continue to rise unabated, many locations in the Alps will end up below the winter zero-degree isotherm which were previously above it, and the number of days with fresh snow can be expected to decrease significantly.

Map of the Alpes with indication of the measurement stations.

In the event that greenhouse gas emissions continue to increase unchecked (RCP8.5 emission scenario), the winter zero-degree isotherm, which is currently around 800 m a.s.l., will rise by several hundred metres as a result of the warming. This means that many stations located at medium altitudes (e.g., Adelboden and Disentis) that today record on average below-zero temperatures over the winter months will experience average temperatures above 0°C by the middle of the century .

In Adelboden, for example, by the middle of this century, the average winter temperature will increase from -1.1°C today to a likely 0.7–1.9°C if greenhouse gas emissions continue to rise unabated (RCP8.5). Because of the increasing winter temperatures, the number of days with fresh snowfall will decrease significantly compared to the present. Just over half the number of fresh snowfall days compared to today are expected in Adelboden, Disentis, and Zermatt by the middle of the century.

In the summer months, the extent of the warming is generally more pronounced in the Alps than in the lowlands and tends to increase with altitude. Without climate change mitigation (RCP8.5), stations in the valleys, such as Chur, will have summer temperatures similar to those recorded on average at the warmest stations in Ticino today. The higher-altitude stations of Adelboden and Zermatt will possibly see temperatures that are typical of the Swiss Plateau. Similarly, the number of summer days (i.e., days on which the temperature exceeds 25°C) experienced in Zermatt by the middle of the century will correspond to that recorded in Bern today.

The projected changes in precipitation in winter are generally less pronounced, percentage-wise, than in the lowlands, whereas the changes in the summer months are similar in the two regions. In Adelboden, for example, the current average summer precipitation is 150 mm per month. Summer precipitation without climate change mitigation (RCP8.5) is projected to be between 110 mm and 154 mm per month by the middle of the century, thus ranging from a slight increase to a significant decrease. In the same scenario, winter precipitation is projected to range from 92 mm to 117 mm per month (compared to 93 mm per month today).

What do RCP2.6 and RCP8.5 mean? You can find an explanation of the emission scenarios here.

What does "the middle of the century" mean? You can find an explanation of the CH2018 time periods here.

Tables

In the following tables, the seasonal absolute values for temperature, precipitation, and certain climate indicators for the present (standard period 1981–2010) and for the two emission scenarios (RCP2.6 and RCP8.5) around the middle of the century (2060) are shown for a selection of monitoring stations in the Alps.

You can find data on other monitoring stations in the CH2018 web Atlas.

Temperature

		Temperature in winter (°C)			Temperature in summer (°C)
Stations	m a.s.l.[C1]	Situation today	Situation around 2060		Situation today	Situation around 2060
			RCP2.6	RCP8.5		RCP2.6	RCP8.5
Adelboden	1322	-1.1	-0.5 to +0.6	+0.7 to +1.9	+13.5	+14.5 to +16.4	+16.1 to +19.4
Chur	556	+1.1	+1.7 to +3.1	+3.1 to +4.3	+18.0	+18.8 to +20.3	+20.3 to +23.0
Disentis	1197	-1.1	-0.4 to +0.9	+0.9 to +1.9	+14.6	+15.7 to +17.5	+17.2 to +20.5
Interlaken	577	+0.2	+1.0 to +2.1	+1.9 to +3.0	+17.2	+17.9 to +19.0	+19.2 to +21.0
Samedan	1708	-8.3	-7.3 to -5.8	-5.7 to -4.6	+11.1	+11.9 to +13.9	+13.2 to +15.9
Visp	639	-0.3	+0.8 to +1.9	+2.2 to +3.3	+18.4	+19.1 to +20.8	+20.5 to +23.0
Weissfluhjoch	2691	-8.1	-7.7 to -6.3	-6.4 to -5.3	+4.9	+6.0 to +7.5	+7.5 to +10.3
Zermatt	1638	-3.6	-2.8 to -1.9	-2.0 to -0.8	+12.5	+13.5 to +16.2	+15.2 to +19.1

The 'situation today' represents the actual measured seasonal average temperature over the normal period of 1981 to2010. The 'situation around 2060' gives the relevant projections for the period from 2045 to 2074.

Legend

At the Disentis monitoring station, for example, by the middle of this century (2060), the average winter temperature may increase from -1.1°C today to up to +1.9°C if greenhouse gas emissions continue to rise unabated (RCP8.5). In this scenario, an average summer temperature of between 17.2°C and 20.5°C is possible (compared to 14.6°C today). With consistent climate change mitigation (RCP2.6), the increase in winter temperatures in Disentis can be moderated, with average temperatures reaching -0.4°C to +0.9°C by 2060. In summer, temperatures will only rise to around 15.7–17.5°C.

Top of page

Precipitation

		Winter precipitation (mm/month)			Summer precipitation (mm/month)
Stations	m a.s.l.	Situation today	Situation around 2060		Situation today	Situation around 2060
			RCP2.6	RCP8.5		RCP2.6	RCP8.5
Adelboden	1322	93	87 to 111	92 to 117	150	116 to 150	110 to 154
Chur	556	51	49 to 66	54 to 70	104	74 to 104	63 to 113
Disentis	1197	63	58 to 82	62 to 85	111	86 to 122	80 to 125
Interlaken	577	74	69 to 96	78 to 98	134	96 to 136	78 to 132
Samedan	1708	27	28 to 39	26 to 41	88	66 to 100	65 to 106
Visp	639	52	48 to 65	52 to 69	43	34 to 49	29 to 53
Weissfluhjoch	2691	94	86 to 111	94 to 120	175	127 to 167	110 to 175
Zermatt	1638	41	37 to 60	37 to 53	61	43 to 67	44 to 65

The ‘situation today’ represents the actual measured seasonal average precipitation over the normal period of 1981 to 2010. The ‘situation around 2060’ gives the relevant projections for the period from 2045 to 2074.

Legend

At the Adelboden monitoring station, the current average precipitation is 150 mm per month during the summer months. During the period around 2060, the summer precipitation trend without any climate change mitigation (RCP8.5) shows a decrease: Between 110 mm and 154 mm per month can be expected. In the same scenario, the winter precipitation trend indicates a likely increase from 93 mm to 92–to117 mm per month. If comprehensive measures are implemented to reduce greenhouse gas emissions (RCP2.6), the changes in precipitation can be mitigated slightly. In summer, precipitation would then be between 116 mm and 150 mm per month (compared to 150 mm per month today), and in winter, between 87 mm and 111 mm per month (compared to 93 mm per month today).

Top of page

Summer days

Definition of a summer day

Stations	m a.s.l.	Summer days now	Summer days around 2060
			RCP2.6	RCP8.5
Adelboden	1322	7	11 to 23	23 to 61
Chur	556	49	58 to 73	76 to 102
Disentis	1197	19	28 to 41	43 to 75
Interlaken	577	39	50 to 64	65 to 91
Samedan	1708	2	5 to 13	14 to 40
Visp	639	64	76 to 97	97 to 127
Weissfluhjoch	2691	0	0	0 to 1
Zermatt	1638	6	11 to 27	27 to 76

‘Summer days now’ represents the actual recorded number of summer days per year, averaged over the normal period of 1981 to 2010. ‘Summer days around 2060’ gives the relevant projections for the period from 2045 to 2074.

Legend

Currently, the monitoring station of Interlaken observes an average of 39 summer days (temperature of at least 25°C) per year. Without climate change mitigation (RCP8.5), there could be up to 91 summer days per year in Interlaken by the middle of this century (2060). With consistent implementation of climate change mitigation (RCP2.6), the increase would be less drastic, up to 64 summer days.

Top of page

Tropical nights

Definition of a tropical night

Stations	m a.s.l.	Tropical nights now	Tropical nights around 2060
			RCP2.6	RCP8.5
Adelboden	1322	0.0	0.0 to 0.1	0.0 to 2.9
Chur	556	0.1	0.6 to 2.5	2.8 to 15.2
Disentis	1197	0.0	0.0 to 0.2	0.1 to 3.4
Interlaken	577	0.0	0.1 to 1.0	0.8 to 5.6
Samedan	1708	0.0	0.0	0.0
Visp	639	0.1	0.0 to 0.4	0.3 to 4.0
Weissfluhjoch	2691	0.0	0.0	0.0
Zermatt	1638	0.0	0.0	0.0 to 0.2

‘Tropical nights now’ represents the actual recorded number of tropical nights per year, averaged over the normal period of 1981–2010. ‘Tropical nights around 2060’ gives the relevant projections for the period from 2045 to 2074.

Legend

At the Chur monitoring station, tropical nights are an exception in the current climate (over the normal period of 1981–2010), with 0.1 per year. By the middle of this century (2060), there could be 15.2 tropical nights per year at this station. With consistent climate change mitigation (RCP2.6), the average number of tropical nights would be limited to up to 2.5 per year.

Top of page

Frost days

Definition of a frost day

Stations	m a.s.l.	Frost days now	Frost days around 2060
			RCP2.6	RCP8.5
Adelboden	1322	136	105 to 131	88 to 110
Chur	556	84	57 to 77	45 to 61
Disentis	1197	128	99 to 123	83 to 101
Interlaken	577	100	74 to 96	60 to 76
Samedan	1708	235	199 to 222	175 to 200
Visp	639	114	87 to 110	71 to 90
Weissfluhjoch	2691	263	226 to 250	195 to 223
Zermatt	1638	173	150 to 171	132 to 153

‘Frost days now’ represents the actual recorded number of frost days per year, averaged over the normal period of 1981–2010. ‘Frost days around 2060’ gives the relevant projections for the period from 2045 to 2074.

Legend

The monitoring station of Samedan observes an average of 235 frost days (minimum temperature below 0°C) per year. Without climate change mitigation (RCP8.5), the number of frost days in Samedan is projected to decrease to 175–200 per year by the middle of this century (2060). With consistent climate change mitigation, there will be a smaller reduction in the number of frost days per year, to 199–222.

Top of page

Days with fresh snowfall

Definition of a day with fresh snow

Stations	m a.s.l.	Days with fresh snowfall now	Days with fresh snowfall around 2060
			RCP2.6	RCP8.5
Adelboden	1322	42	24 to 40	18 to 32
Chur	556	13	6 to 15	4 to 11
Disentis	1197	34	15 to 28	11 to 23
Interlaken	577	17	13 to 24	9 to 19
Samedan	1708	28	20 to 36	18 to 29
Visp	639	11	7 to 14	4 to 11
Weissfluhjoch	2691	105	86 to 103	76 to 93
Zermatt	1638	30	17 to 29	14 to 24

‘Days with fresh snowfall now’ represents the actual recorded number of fresh snowfall days per year, averaged over the normal period of 1981 to 2010. ‘Days with fresh snowfall around 2060’ gives the relevant projections for the period from 2045 to 2074.

Legend

During the normal period of 1981 to 2010, the Weissfluhjoch monitoring station recorded an average of 105 days with fresh snowfall (a minimum of 1 mm of precipitation falling in the form of snow) per year. Without climate change mitigation (RCP8.5), the number of days with fresh snowfall per year will decrease to 76–93 at the Weissfluhjoch station by the middle of the century (2060). With consistent climate change mitigation (RCP2.6), there will be a smaller reduction in the number of days of fresh snowfall per year, to 86–103.

Top of page

Charts

The interactive charts for all indicators use Zermatt as an example. You can find the figures for other stations in the CH2018 web Atlas.

Zermatt

What do RCP2.6 and RCP8.5 mean? You can find an explanation of the emission scenarios here.

Last modification 26.06.2024