EU summertime arrangements - what is it about?

Summertime arrangements in the EU require that the clocks are changed twice per year in order to cater for the changing patterns of daylight and to take advantage of the available daylight in a given period.

The majority of the EU Member States have a long tradition of summertime arrangements, most of which date back as far as the First and Second World Wars or to the oil crisis in the 1970s. At the time, summertime arrangements were mainly designed to save energy. However, there have also been other motivations, such as road safety, increasing leisure opportunities stemming from longer daylight during evenings or simply to align national practices to those of neighbours or main trading partners.

Summertime arrangements at EU level exist since the 1980s and are currently governed by Directive 2000/84/EC. The Directive sets out the obligation on Member States to switch to summertime on the last Sunday of March and to switch back to wintertime on the last Sunday of October. The objective of EU legislation on summertime was to unify existing national summertime schedules that were diverging, thereby ensuring a harmonised approach to the time switch within the single market.

In parallel to, and independent from, the EU summertime arrangements, Member States are grouped into three different time zones or standard times. The decision on the standard time is as such not affected by the EU summertime rules (or any change thereof). (EU Member States today stretch over three time zones: Western European Time or Greenwich Mean Time (GMT), Central European time (GMT+1), and Eastern European Time (GMT+2). Eight Member States in the Union (Bulgaria, Cyprus, Estonia, Finland, Greece, Latvia, Lithuania and Romania) apply GMT+2 as their standard time. 17 Member States (Austria, Belgium, Croatia, Czech Republic, Denmark, France, Germany, Hungary, Italy, Luxembourg, Malta, the Netherlands, Poland, Slovak Republic, Slovenia, Spain and Sweden) apply GMT+1 and three Member States (Ireland, Portugal and United Kingdom) apply GMT.) It is determined in relation to GMT (Greenwich Mean Time) or UTC (Coordinated Universal Time).

It should also be noted that the availability of daylight varies according to EU Member States' geographical location. Northern EU Member States have a relatively large seasonal change in available daylight in the course of the year, characterised by dark winters with little daylight and bright summers with short nights. For the Southernmost EU Member States the day and night distribution of daylight scarcely alters during the year (See solar timetables in EU Member States).

Are current EU summertime arrangements working?

A number of studies have been carried out over the years to assess EU summertime arrangements. Available evidence indicates the following (For more details, please see list of main reference documents at the end. It refers to official Commission documents and reports, as well as the most recent meta-studies that analyse available scientific reports and studies on this issue):

Internal market: At this juncture, evidence is only conclusive on one point: that allowing uncoordinated time changes between Member States would be detrimental to the internal market due to higher costs to cross-border trade, inconveniences in transport, communications and travel, and lower productivity in the internal market for goods and services.

At this juncture, evidence is only conclusive on one point: that allowing uncoordinated time changes between Member States would be detrimental to the internal market due to higher costs to cross-border trade, inconveniences in transport, communications and travel, and lower productivity in the internal market for goods and services. Energy: Despite having been one of the main drivers of the current arrangements, research indicates that the overall energy savings effect of summertime is marginal. Results also tend to vary depending on factors such as geographical location.

Despite having been one of the main drivers of the current arrangements, research indicates that the overall energy savings effect of summertime is marginal. Results also tend to vary depending on factors such as geographical location. Health: Summertime arrangements are estimated to generate positive effects linked to more outdoor leisure activities. On the other hand, chronobiologic research findings suggest that the effect on the human biorhythm may be more severe than previously thought. The evidence on overall health impacts (i.e. the balance of the assumed positive versus negative effects) remains inconclusive.

Summertime arrangements are estimated to generate positive effects linked to more outdoor leisure activities. On the other hand, chronobiologic research findings suggest that the effect on the human biorhythm may be more severe than previously thought. The evidence on overall health impacts (i.e. the balance of the assumed positive versus negative effects) remains inconclusive. Road safety: Evidence remains inconclusive with regard to the relationship between summertime arrangements and road traffic accidents. In principle, sleep deprivation from advancing the clock in spring could increase the risk of accidents. At the same time, extended daylight hours during summer evenings are considered to have a positive effect on road safety. However, it is generally difficult to attribute directly the effect of summertime arrangements on accident rates compared to other factors.

Evidence remains inconclusive with regard to the relationship between summertime arrangements and road traffic accidents. In principle, sleep deprivation from advancing the clock in spring could increase the risk of accidents. At the same time, extended daylight hours during summer evenings are considered to have a positive effect on road safety. However, it is generally difficult to attribute directly the effect of summertime arrangements on accident rates compared to other factors. Agriculture: Previous concerns regarding disrupted biorhythm of animals and changing milking schedules due to the time switch appear to have largely disappeared due to the deployment of new equipment, artificial lighting and automated technologies. An extra daylight-hour during summer can also be an advantage allowing extended working hours for outdoor activities, such as working in fields and harvesting.

The Commission regularly receives feedback from citizens on the summertime issue, which often refer to what they perceive as negative health impacts of the disruptive time change relating to sleep deprivation and other kinds of negative consequences. However, some also ask that the current system be maintained, as they believe it has positive effects.

Some Member States have recently addressed the summertime issue in letters to the Commission. More specifically, Finland has asked that the bi-annual time switch be abandoned and Lithuania has called for a review of the current system in order to take into account regional and geographical differences.

The European Parliament adopted a resolution in February 2018, asking the Commission to conduct a thorough assessment of the Directive and, if necessary, come up with a proposal for its revision. At the same time, the resolution confirmed that "it is essential to maintain a unified EU time regime even after the end of biannual time changes".

Way forward?

Available evidence suggests that common rules in this area are critical to ensure the proper functioning of the internal market. This is also supported by the European Parliament, which in its resolution stated that it is crucial to maintain a unified EU time regime.

In response to the European Parliament resolution, the Commission has therefore committed to assess the two main policy alternatives available to ensure such a harmonised regime, which are: