Stockholm Historical Weather Observations — Thermometer observations since 1756

Anders Moberg

Weather observations have been made continuously at the old astronomical observatory in Stockholm since 1754. The dataset provided here contains individual air temperature observations for the period 1756⁠–⁠2018.

The dataset mostly contains between two and five observations per day. All measurements are made in degree Celsius (°C).

These data have been used to derive continuous series of daily, monthly, seasonal and annual mean temperatures for Stockholm since 1756.

Citation

Anders Moberg (2019) Stockholm Historical Weather Observations — Thermometer observations since 1756. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/stockholm-historical-thermometer-1

References

Moberg A, Bergström H, Ruiz Krigsman J, Svanered O. 2002: Daily air temperature and pressure series for Stockholm (1756–1998). Climatic Change 53: 171–212. https://doi.org/10.1023/A:1014966724670

Data description

Data with temperature observation values are provided in separate files for the following time periods:

1756⁠ – 1858

1859⁠ – 1960

1961⁠ – 2012

2013⁠ – 2018

For the last period, data are provided separately for both a manual and an automatic weather station.

All data are availabe in two file formats:

1. plain text files (.txt)

2. tab-separated value files (.tsv)

Detailed description of the content in each file is found in a README text file.

The data have been quality controlled as described by Moberg et al. (2002), but are not subject to any homogenization or correction for known instrumental biases.

Comments

The observation site is included in the national station network managed by the Swedish Meteorological and Hydrological Institute (SMHI), with station number 98210 (manual station) and 98230 (automatic station), but data in the current dataset can differ from those in the SMHI database.

The number of observations each day has changed through time, as follows:
1756⁠ – 1760: 2 observations (morning and noon)
1761⁠ – 1858: 3 observations (morning, noon, evening)
1859⁠ – 2018: 5 observations (morning, noon, evening, min, max).

Observation times for all morning, noon and evening observations are provided in a separate dataset.

During 1756–1875, the thermometer was hung in the free air outside a north-facing window on the second floor of the old astronomical observatory building. No detailed description is available for how the thermometer was placed or protected from radiation.

During 1876–1960, the thermometer was placed outside a north-facing window on the first floor of the old astronomical observatory building. A window-screeen was in use since 1878.

During 1961 to summer 2006, the thermometer was placed in an SMHI (Stevenson-type) screen about ten metres north-east of the former position.

In summer 2006, a platinum resistance thermometer in a modern cylindrical screen close to the SMHI screen replaced the mercury thermometer in the SMHI screen.

From January 2013 onwards, data are provided separately for both the manual station and the automatic weather station. Although the automatic station records temperature every hour, the current dataset only contains data for the same observation times as for the manual observations for the sake of consistency.

Original data sources used to produce this dataset:
1756⁠ – 1858: Handwritten observation journals from the archive of the Royal Swedish Academy of Sciences.
1859⁠ – 1861: Handwritten observation journals from the archive of the SMHI.
1862⁠ – 1960: Printed tables in the meteorological year-books "Meteorologiska Iakttagelser i Sverige", published by the SMHI or its predecessors.
1870–1899: Handwritten observation journals from the archive of the SMHI (for daily maximum and minimum temperatures only).
1961⁠ – 2012: Computer files provided by the SMHI through personal contacts.
2013⁠ – 2018: Data files downloaded from the SMHI resource Öppna Data, subject to subsequent checking and correction for errors.

A small number of individual temperature values in the data files may deviate from the ones given in the handwritten sources, in cases when the latter were judged to be incorrect by Moberg et al. (2002; see section 3.2).

Thermometer observation data in this dataset are used to derive the corresponding datasets with daily mean air temperatures and monthly mean air temperatures.