Where weather sits versus normal (MERRA-2, monthly)
What it measures. Shows how a given month's weather ranks against normal, using percentiles for temperature (high, average and low) and total precipitation, to flag unusually extreme conditions.
How it's made. Computed from NASA's MERRA-2 reanalysis by comparing monthly values against a 30-year baseline (1991-2020); it's a model-based product, not a single instrument's data.
How & where you'd use it. Helps identify and characterize extreme heat, cold, wet or dry months for climate and disaster research.
What's measured
Coverage & cadence
- Time span1980-01-01 → ongoing
- Measured byMERRA-2 (NOT APPLICABLE)
- Processing levelLevel 4
- Spatial extent-180, -90, 180, 90
- StatusACTIVE
What you can do with it
- Map air pollutants — NO₂, aerosols, ozone
- Track greenhouse gases and Earth's energy budget
- Feed weather and air-quality analysis
Official description
M2SMNXPCT (or statM_2d_pct_Nx) is a 2-dimensional monthly data collection for percentile statistics derived from monthly Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) datasets. V2 of this percentile data collection is computed based on the 1991-2020 climatology, covering the time period from January 1980 to present. In contrast, V1, the original version, is computed based on an earlier 30-year climatology (1981-2010). This collection consists of percentiles used to identify or characterize extreme weather events associated with temperature (maximum, mean, and minimum 2-m air temperature), as well as with precipitation (total precipitation). MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by the NASA Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980-present, with a latency of ~3 weeks after the end of the previous month. Data Reprocessing: Please check “Records of MERRA-2 Data Reprocessing and Service Changes”, linked from the “Documentation” tab on this page. Note that a reprocessed data filename is different from the original filename. MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changes to tools and services, as well as data announcements from GMAO. Contact the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov) to be added to the list. Questions: If you have a question, please read the "MERRA-2 File Specification Document'', “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page for more information. If these documents do not answer your question, you may post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="M2SMNXPCT",
version="2",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from GES_DISCBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- Documents with exmaple on how to read and plot MERRA-2 data. VIEW RELATED INFORMATION
- File Specification Document VIEW RELATED INFORMATION
- Access the data via HTTPS. GET DATA
- Use the Earthdata Search to find and retrieve data sets across multiple data centers. GET DATA
- Access the data via the OPeNDAP protocol. USE SERVICE API
- RREADME Document VIEW RELATED INFORMATION
- MERRA-2 Data Access – Quick Start Guide VIEW RELATED INFORMATION
- Records of MERRA-2 Data Reprocessing and Service Changes VIEW RELATED INFORMATION