Daily mean air temperatures from Tarfala Research Station, Kebnekaise mountains, northern Sweden
Tarfala Research Station Staff
This dataset contains daily mean air temperatures from Tarfala Research Station (TRS), acquired since 1965 and updated since. It details TRS’ monthly mean average temperature data set, which is published separately.
Tarfala Research Station, located at 1135 m a.s.l. in the Tarfala Valley, Kebnekaise Mountains, Northern Sweden, is Stockholm University’s centre for glaciological and alpine research. Here, meteorological observations have been carried out regularly since the mid 1940’s, already before TRS was inaugurated in 1961. Daily mean air temperatures provide important climatological information in itself, and can also be used to derive e.g. annual Positive Degree Day (PDD) sums, which are annual sums of daily mean temperatures above zero and are typically used to quantify the energy available for melting of snow and ice.
In 1987 the first digital logger based automatic weather station (AWS) was established and operated until 2013 when it was replaced by a more modern equivalent (referred to as TRS-AWS). The dataset presented here is compiled from some previously published separate datasets containing data until 2011, and is here updated to include data until 2025 from TRS-AWS.
AtmosphereTemperatureAir temperatureTarfalaKebnekaiseWeatherArcticAlpineDaily data
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Citation
References
Jonsell U, Hock R, Duguay M (2013) Recent air and ground temperature increases at Tarfala Research Station, Sweden. Polar Research 32:19807. https://doi.org/10.3402/polar.v32i0.19807
Tarfala Research Station staff (2026) Monthly mean air temperatures from Tarfala Research Station, Kebnekaise mountains, northern Sweden. Dataset version 3. Bolin Centre Database. https://doi.org/10.17043/tarfala-monthly-temperature-3
Data description
The data file tarfala-daily-temperature-1-1965-2025.csv provides daily mean temperatures since 1965 as a table. The table has 62 columns:
dateTime, given as day of the year (DD-MM)1965Daily averaged temperatures (°C) for 19651966Daily averaged temperatures (°C) for 1966- ...
2025Daily averaged temperatures (°C) for 2025
The table has 367 rows, including the header row; one for each day of the year, including, for all years, 29 February (date = 29-02). This row is only filled in for leap years.
Comments
Dataset compilation
The dataset presented here is compiled from some previously published separate datasets, and expanded thereafter:
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Daily temperature data for the years 1965 to 2011 was originally published by Jonsell et al. (2013). They also provided information on how gaps in the raw data were filled. In the current dataset, the data are occasionally rendered with higher decimal accuracy, or with slightly different values (up to 0.3 °C difference), based on inspection of the original raw data files.
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For the years 2012 and 2013, data was originally published under Tarfala Data — Climate. Missing values in the raw data files (31 Dec 2012 and 16 June - 4 July 2013) are filled with values from SMHI Tarfala A Station where possible.
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For the year 2014, missing values from TRS-AWS between 30 March and 8 April are indicated by
NaNand could not be filled with data from the SMHI Tarfala A station, as it, too, has no data. Missing values from TRS-AWS on 7-8 August are filled with values from SMHI Tarfala A Station. -
For the years 2015 (from January) to 2021 (until end of March), data from TRS-AWS was originally published at SITES. Data gaps (14 -21 January and 31 January 2015) are filled with values from SMHI Tarfala A Station.
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From 1 April 2021 onwards, data is from TRS-AWS and annually updated here. Data gaps occur between 27 October 2022 and 30 April 2023, and in 2025 between 23 March and 7 August, and between 20 August and 4 September. These gaps are filled with values from SMHI Tarfala A Station.
Data since 2021 was appended by Nina Kirchner.
Highlights
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The highest daily averaged temperatures occurred in 2018 (17 July: 19 °C) and in 2021 and 2019 (4 July and 27 July, respectively: 18 °C).
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The lowest daily averaged temperatures occurred in 1966 (25 December: -33°C) and in 1979, 2010 and 2012 (26 January, 23 February, and 6 February, respectively: -29 °C).
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The highest annual Positive Degree Day (PDD) sum was attained in 2024 (1166 °C), while the lowest was attained in 1975 (424 °C). To compute an annual PDD sum, all daily averaged temperatures above 0 °C in a particular year are summed.
Related dataset
- Monthly mean air temperatures from Tarfala Research Station, Kebnekaise mountains, northern Sweden (Tarfala Research Station staff, 2026).
Project
Tarfala Research Station programme
Publisher
Bolin Centre Database
License
Open Data Commons Attribution License (ODC-By) v1.0
First name
Nina
Last name or organisation
Kirchner
Email address
Address
Tarfala Research Station, Baltic Sea Centre and Department of Physical Geography; Stockholm University
Postal code
SE-106 91
City
Stockholm
Country
Sweden
GCMD science keyword
Earth science > Atmosphere > Atmospheric temperature > Surface temperature > Air temperature
GCMD location
Continent > Europe > Northern Europe > Scandinavia > Sweden
Dataset language
English
Begin date
1965-01-01
End date
2025-12-31