Estonian Climate Data Explorer

About this project

The Estonian Climate Data Explorer showcases the various public weather datasets available for Estonia: historical weather-station data from 1991 onwards, near-real-time station observations, precipitation intensity from weather radars, and lightning data. We may add further datasets in the future.

The project uses the open data of the Estonian Environment Agency, complemented by EUMETSAT lightning observations and data from the Finnish and Swedish meteorological radars.

Data & sources

The explorer uses the following open datasets:

• Historical climate series — hourly and daily measurements (temperature, humidity, pressure, wind, precipitation) from around 25 Estonian weather stations, from 1991 to the end of 2025, from the Estonian Environment Agency climate dataset.
• Weather radar — precipitation-intensity composites from the Estonian radar network and the Finnish (FMI) and Swedish (SMHI) radars. The data is updated continuously; for operational Estonian data we recommend the Estonian Environment Agency's radar observations.
• Lightning — ground-based lightning detections from the NORDLIS network via FMI, and EUMETSAT MTG Lightning Imager (LI) observations.
• Live station observations — synoptic station reports decoded from WMO BUFR messages. For operational data we recommend the Estonian Environment Agency's weather-observations page.
• Two observation sources in the Weather tab — The Weather tab can show either of two feeds from the Estonian Environment Agency. The BUFR bulletins cover 25 synoptic stations and are the only source of dew point. The ilmateenistus observations XML covers 154 stations — every BUFR station plus 129 more, including many coastal and island sites — and adds weather phenomenon, sunshine, radiation and UV. They are kept separate rather than blended, because their precipitation fields are not the same quantity: BUFR reports an accumulation over its 10-minute reporting interval, the XML a total over the last hour. The XML also keeps no history of its own, so this project stores each hourly snapshot as it is published.
• Hydrological monitoring data — Keskkonnaagentuur publishes the hydrometric network through two distributions that do not carry the same thing, and this tab keeps them apart. The hourly series (f_hydroseire) gives a mean/min/max triplet per hour for water level, water temperature and discharge back to 2012, runs about a day behind, and is the only source of discharge. The real-time XML gives one instantaneous reading per station, refreshed 10 minutes past each hour with no history, and is the only source of air temperature and precipitation at these stations. Coastal water level differs between the two by roughly 500 cm — the offset is consistent but undocumented, so the two are never averaged together. Stations are matched between the feeds on coordinates, because the XML's station codes collide across unrelated sites.

Available variables

Alongside the directly measured quantities, the explorer shows a few variables it derives from the raw observations. These are computed by the project, not delivered by the data providers:

Derived variables

• SPI — Standardized Precipitation Index — precipitation accumulated over a 1-month (SPI-1) or 3-month (SPI-3) window. An index within ±1 means the usual range — about 68% of cases; ±2 is a rarer but still possible amount. More precisely, it is a z-score against the climatology of that same calendar month, fitted with a gamma distribution over a fixed reference period (following the WMO SPI User Guide). Positive values are wetter than the reference normal, negative are drier; |SPI| ≥ 1 is moderate and ≥ 2 extreme. See it in the explorer: Climate → Drought Index · Weather → monthly precipitation series
• Daily precipitation total (24 h) — the 10-minute precipitation readings summed over one day. Note the day boundary: in meteorology a “daily” precipitation total is conventionally accumulated from 06 UTC to 06 UTC the next day, whereas here we sum over the UTC calendar day (00–24 UTC). Values may therefore differ from official daily totals, especially when rain falls near the 06 UTC cut-off.
• Monthly precipitation total — the precipitation summed over a whole calendar month, from the same 10-minute series. This is also the input to the SPI computation.
• Radar 24 h precipitation accumulation — the Estonian radar precipitation rate (mm/h) integrated over a UTC calendar day into a 24 h total (mm), shown as a map overlay in the radar tab's “24h” view and, on the daily station-precipitation graph, as the distribution of radar cells within a 5 km disc around each station (a box plot: median, 25/75 %, min/max). This is an indicative radar estimate, not a gauge measurement — it carries the usual radar biases and any missing scans under-count — so it is not directly comparable to the station daily totals. See it in the explorer: Weather → daily precipitation series

Measured variables

The remaining variables are reported directly by the stations and radars: air temperature, relative humidity, air pressure, wind speed and direction, instantaneous precipitation, radar precipitation intensity (mm/h), and lightning detections.

Licensing & usage

The underlying data is published as open data. Radar and lightning products are licensed under Creative Commons Attribution 4.0 (CC BY 4.0); climate observations come from the Estonian Environment Agency open-data programme. When you reuse the data, please credit the original providers:

• Estonian Environment Agency — climate dataset
• Estonian Environment Agency — radar & lightning dataset
• FMI — open data
• SMHI — open data
• EUMETSAT — MTG Lightning Imager

Creative Commons Attribution 4.0 (CC BY 4.0)

The maps and charts shown here are products derived and processed from these sources — for example rendered radar composites, 24-hour precipitation accumulations, and time-series aggregates — not the providers' original data as issued.

This is a non-commercial project of the University of Tartu Centre for Climate Research; it is not an official product of any data provider. The products are provided “as is”, without warranty; do not rely on them for safety-critical or any other decisions.

Contact

Substantive suggestions can be sent to: info@explorer.kliima.ut.ee