Standard climate normals

New average climate conditions for Lithuania

From 2021 The Lithuanian Hydrometeorological Service under the Ministry of Education and Science started to use the new 1991-2020. the Standard Climate Norm (SCN), which describes normal climate conditions in Lithuania.

Compared to the previously used 1981-2010 SCN, the average annual air temperature in Lithuania increased by 0.5 °C. Whereas in 2020 we said that the average annual air temperature in Lithuania would be 6.9 °C (based on the 1981-2010 SCN), in 2021 it will be 7.4 °C (based on the 1991-2020 SCN). This will remain the case until 2031, when the new SCN for 2001-2030 will be calculated.

SCN – what is it?

SCN – conditions that describe the normal climatic conditions of a given area. We can also refer to the SCN as the long-term average, or to the current climatic conditions in the case of the current climate.

The SCN are averages of climatological data averaged over the following consecutive 30-year periods: from 1 January 1981 to 31 December 2010, from 1 January 1991 to 31 December 2020, and so on. For the calculation of the SCN, standard periods are also used to compare the climates of individual cities, regions or countries. The 30-year period for which the SCN is calculated is often indicated next to the SCN: e.g. The 30-year period is indicated in the table below, where the SCN (1991-2020) or the SCN (1981-2010) is used.

SCN is used to describe current climatic conditions, as it gives at least a general idea of the weather at a given time of year. The SCN is also used to measure the deviation of the weather from normal conditions, for example whether the previous month was warmer or colder than normal.

Why is the SCN calculated from a 30-year average?

Weather conditions in a given area can vary greatly from year to year or month to month. One or a few years cannot describe the climate of a particular place. This is why a 30-year average is used to describe the climate of an area: it is long enough to be unaffected by the exceptional weather conditions of individual years, but not long enough to describe the ongoing changes in climate.

Why and how often do I need to recalculate the SCN?

The SCN is recalculated every 10 years, in line with the recommendations of the World Meteorological Organisation. In the past, it was sufficient to recalculate the SCN every 30 years: 1901-1930, 1931-1960, 1961-1990, but due to rapid climate change, the 30-yearly recalculation of the SCN was no longer in line with actual climate conditions. Therefore, at the 2015 World Meteorological Organisation Congress, it was decided to recalculate the SCN every 10 years, starting from the first year of each decade (1981-2010, 1991-2020, etc.).

The recalculation of the SCN is not only to update the current climatic conditions, but also to assess how the average climatic conditions have changed under the different SCN.

What used to be abnormal is now normal and vice versa?

The “normality” of Lithuania’s climate has changed with the introduction of the new SCN (1991-2020). For example: in 2021 the average air temperature in Lithuania in August was +16.1 °C, which was 1.4 °C cooler than normal compared to the current SCN (1991-2020). But as early as 2020 according to the old SCN (1981-2020), such an August would have been only 1.0 °C cooler than normal, while ten years ago, according to the even older SCN (1961-1990), such an August would have been almost normal for the climate conditions in Lithuania at that time (just 0.1 °C cooler than normal).

What is Lithuania’s climate now and how has it changed compared to 1981-2010 SCN? and 1991-2020 SCN?

The use of SCN can not only describe the normal climatic conditions of a given period, but also describe changes in climate.

Air temperature According to the new SNA (1991-2020), the average annual air temperature in Lithuania is 7.4 °C. The warmest month of the year is July (18.3 °C) and the coldest is January (-2.9 °C).

A comparison of the previously used SCN (1981-2010) and the current SCN (1991-2020) shows that the annual air temperature in Lithuania has risen by 0.5 °C, with the warmest months being December, November and February, and the lowest months being May and October.

1981–2010, °C-3,2-3,20,46,712,415,417,917,112,27,21,9-1,96,9
1991–2020, °C-2,9-2,50,97,212,515,918,317,612,87,32,6-1,17,4
Difference, °C0,30,70,50,50,10,50,40,50,60,10,70,80,5

Precipitation. According to the new SNA (1991-2020), the average annual precipitation in Lithuania is 695 mm. The highest rainfall occurs in July (84 mm) and the lowest in April (37 mm).

A comparison of the previously used SCN (1981-2010) and the current SCN (1991-2020) shows that the annual precipitation in Lithuania has decreased very slightly. Precipitation decreased the most in September June and increased in February.

1981–2010, mm523842375475787766665956698
1991–2020, mm534339375368847760685756695
Difference, %213-70-2-980-93-300

Average wind speed. The average annual wind speed according to the new SNA (1991-2020) in Lithuania is 3.1 m/s. The windiest months are November-February (3.4-3.6 m/s), while the windiest months are July and August (2.4-2.5 m/s).

Compared to the previous SCN (1981-2010), the average annual wind speed in Lithuania decreased by 0.2 m/s. The largest changes occurred in January (-0.4 m/s) and August-November (-0.3 m/s).

1981–2010, m/s4,03,73,53,23,02,92,72,73,03,43,73,73,3
1991–2020, m/s3,63,53,33,12,82,72,52,42,73,13,43,63,1

Duration of sunshine. On average, the Sun shines for 1,917 hours per year according to the new SNA (1991-2020). The sunniest months are May and July (283 hours) and the least sunny is December (29 hours).

Compared to the previous SCN (1981-2010), the duration of sunshine has increased by 2% (100 hours), with the largest increases in January, March and April. (7-10%), while decreased in November (-7%).

1981–2010, hr.386413219927826628825717010742291871
1991–2020, hr.416514521228327728325817910639291917
Difference, %8210724-205-1-702

More information on the magnitudes of the meteorological elements from 1991-2020. SCN can be found here (in Lithuanian): Standartinė klimato norma 1991–2020 m. (PDF)

Assessment of climate change in Lithuania, 1961-1990 and 1991–2020 m. standard climate normals

Despite the fact that the SCN is currently recalculated every 10 years, changes in normal climatic conditions can be reasonably well described by comparing SCN for non-overlapping years. This is one way of looking at climate change. Therefore, in order to assess how the normal climatic conditions used to describe climate have changed, we have compared two SCNs calculated from non-overlapping years: 1961-1990. and 1991–2020 m. and assessed how the climate has changed. The comparison, illustrated with maps and tables, can be found here (in Lithuanian): Assessment of climate change in Lithuania, 1961-1990 and 1991–2020 m. standard climate normals

Hydrometeorological datasets

Air temperature (mean/minimum/maximum) and precipitation (daily, 1991-2020)
Air temperature, precipitation, wind, sun, humidity, pressure (SKN 1991-2020)

Daily air temperature records
Daily mean air temperaturera (SCN 1991-2020)
Active temperature sums (SCN 1991-2020)
Temperature transitions over 0, 5, 10 and 15 degrees (SCN 1991-2020)

Soil freezing depth (2005-2023 )
Soil surface frost (SCN 1991-2020)

Average number of days with precipitation  (SCN 1991-2020)
Snow depth and number of days with snow cover (SKN, 1991-2020)

Solar parameters daily and monthly data (1954-2022 )
Duration of sunshine (monthly sums, 1961-2022 )
Solar radiation (SCN 1991-2020)
Total ozone (1993-2022 averages)
Total  ozone (daily and monthly averages, 1993-2022)

Wind roses (SCN 1991-2020)

Lightning discharges (2013-2017)
Lightning discharges (2018-2022)

Hydrological yearbooks 2016-2018 (PDF)
Hydrological yearbooks 2019-2021 (PDF)
Hydrological yearbooks 2022 (PDF)

Maps (temperature, precipitation, sun, wind, snow, etc.) (PNG)

All hydrometeorological datasets are publicly available and free of charge for public use, dissemination and further processing, subject to the terms and conditions of use:
1) the data may only be used for legitimate and specified purposes;
2) when publishing, reproducing or otherwise using the data, it is necessary to indicate that the source of the data is LHMT (Lithuanian Hydrometeorological Service).