Midas-open is the open data version of the Met Office Integrated Data Archive System (MIDAS) for land surface station data (1853 – present). It contains land surface observations data from the Met Office station network that have been designated as public sector information and provided under an Open Government Licence.

Midas-open is a subset of the fuller Met Office Integrated Data Archive System (MIDAS) Land and Marine Surface Stations Data (1853-current), containing only UK mainland land surface observations owned or operated by Met Office. Currently this represents approximately 95% of available daily temperature and weather observations, 83% of hourly weather data, and 13% of daily rainfall within the full MIDAS collection. A large proportion of the UK raingauge observing network is operated by other agencies so currently excluded from the Midas-open set. It does not supersede the full MIDAS collection also archived at CEDA.

MIDAS Open comprises of hourly and daily weather measurements and observations of parameters relating to temperature, rainfall, sunshine, radiation, wind and weather observations such as present weather codes, cloud cover, snow etc. This dataset collection is updated annually in a delayed mode to ensure that data acquisition and quality control procedures have all been completed. Data are available from 1853 or later years, depending on the data in question. Note: not all sites operated for the entire date span; some sites were opened in later years, whilst others were closed in subsequent years. Each version of the dataset will include data for a full year upto around the 12 months previous to the year-month in the version of the dataset (e.g. v201901 included data up until the end of 2017).