About this site
This site provides a simple interface to view climate observations from around the world. The site was originally designed with data for Australia, New Zealand and Central England. Those regions have daily temperature and precipitation datasets.
The rest of the world has temperature and precipitation values coming from monthly datasets (from GHCNm).
Other types of data come from various other sources, described below.
All data is from instrument-based recordings. There is no proxy data (for example, using tree rings or ice-cores to estimate temperature) nor modelled data on this website. The developers of the website are not sceptical of proxy-data or modelling but wanted to present the most simple and easily understandable climate science.
Source code
The source code for this website is at the ClimateExplorer Github. There is an issues area where bugs can be raised and suggestions for improvements can be submitted.
Data sources
Australian Bureau of Meteorology
Australian Climate Observations Reference Network - Surface Air Temperature
The Australian Climate Observations Reference Network - Surface Air Temperature (ACORN-SAT) data set is a homogenized daily maximum, minimum and mean temperature data set containing data from 112 locations across Australia extending from 1910 to the present.
Australian Bureau of Meteorology Climate Data Online
Climate Data Online (CDO) provides historical daily rainfall and maximum and minimum temperature observations from Bureau of Meteorology weather stations across Australia. The period of record varies by station and weather element, with some observations dating to the mid-1800s. Data are available from both operating and closed stations, and recent observations may not yet have completed quality control.
CDO also provides precipitation, solar radiation, and unadjusted minimum and maximum temperature. These are downloaded for the sites listed in ACORN-SAT and combined with it into a unified representation of the 112 locations.
Indian Ocean Dipole
Indian Ocean Dipole (IOD) events are driven by changes in the tropical Indian Ocean. Sustained changes in the difference between normal sea surface temperatures in the tropical western and eastern Indian Ocean are what characterise IOD events.
The IOD is commonly measured by an index (sometimes referred to as the Dipole Mode Index, or DMI) that is the difference between sea surface temperature (SST) anomalies in two regions of the tropical Indian Ocean (see map above):
IOD west: 50°E to 70°E and 10°S to 10°N
IOD east: 90°E to 110°E and 10°S to 0°S
A positive IOD period is characterised by cooler than average water in the tropical eastern Indian Ocean and warmer than average water in the tropical western Indian Ocean. Conversely, a negative IOD period is characterised by warmer than average water in the tropical eastern Indian Ocean and cooler than average water in the tropical western Indian Ocean.
For monitoring the IOD, Australian climatologists consider sustained values above +0.4 °C as typical of a positive IOD, and values below −0.4 °C as typical of a negative IOD.
National Oceanic and Atmospheric Administration (NOAA)
Global Historical Climatology Network
Global Historical Climatology Network monthly (GHCNm)
The Global Historical Climatology Network monthly (GHCNm) dataset provides monthly climate summaries from thousands of weather stations around the world. The initial version was developed in the early 1990s, and subsequent iterations were released in 1997, 2011, and most recently in 2018. The period of record for each summary varies by station, with the earliest observations dating to the 18th century. Some station records are purely historical and are no longer updated, but many others are still operational and provide short time delay updates that are useful for climate monitoring.
Global Historical Climatology Network (GHCN) Monthly Precipitation
The Global Historical Climatology Network (GHCN) Monthly Precipitation, Version 4 is a collection of worldwide monthly precipitation values offering significant enhancement over the previous version 2. It contains more values both historically and for the most recent months. Its methods for merging records and quality control have been modernized.
Global Historical Climatology Network daily (GHCNd)
The Global Historical Climatology Network daily (GHCNd) is an integrated database of daily climate summaries from land surface stations across the globe. GHCNd is made up of daily climate records from numerous sources that have been integrated and subjected to a common suite of quality assurance reviews.
Global Historical Climatology Network daily (GHCNd) precipitation
The Global Historical Climatology Network daily (GHCNd) is an integrated database of daily climate summaries from land surface stations across the globe. GHCNd is made up of daily climate records from numerous sources that have been integrated and subjected to a common suite of quality assurance reviews.
Global Monitoring Laboratory
The Global Monitoring Laboratory (GML) of the National Oceanic and Atmospheric Administration (NOAA) conducts research that addresses three major challenges: greenhouse gas and carbon cycle feedbacks, changes in clouds, aerosols, and surface radiation, and recovery of stratospheric ozone.
The Carbon Dioxide (CO₂), Methane (CH₄), N₂O, Mauna Loa atmospheric transmission and ODGI data in ClimateExplorer are sourced from GML.
Physical Sciences Laboratory
Niño 3.4
The Niño 3.4 index is calculated as a 3-month running average of sea surface temperature measurements around the equator in the East Pacific (5 deg N to 5 deg C, 170 deg W to 120 deg W), and then expressed as an anomaly (i.e. difference from the average).
Niño 3.4 conditions of +0.4 deg C or higher are considered El Niño, and -0.4 deg C or lower are considered La Niña.
Atlantic Multidecadal Oscillation
The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of 60-80 years.
This AMO time-series is from NOAA/NCEI, using the ERSSTV5 dataset. It is a sea-surface temperature anomaly (SSTA) North Atlantic 0-60N. ERSSTV5 is used in preference to the original Kaplan SST dataset, because Kaplan SST is no longer updated.
Ocean acidity
Station ALOHA (22°45'N, 158°00'W) is a deep water (~4,800 m) location approximately 100 km north of the Hawaiian Island of Oahu. The Hawaii Ocean Time-series (HOT) surface CO₂ system data product (HOT_surface_CO2.txt) is created after taking cruises to the station (every 1-2 months) for measurements, beginning in 1988.
The mean seawater pH is calculated from the mean seawater dissolved inorganic carbon (DIC - equal to the total CO₂) concentration and mean seawater total alkalinity (TA) at 25 °C, on the total scale.
Total solar irradiance
The Solar Irradiance Climate Data Record (CDR) includes a composite observational record of total solar irradiance (TSI) constructed from space-based radiometer composite records between 1978 and 2014 and Total Irradiance Monitor (TIM) observations after the launch of the SOlar Radiation and Climate Experiment (SORCE). The SORCE TIM record ended Feb 25, 2020. The TSIS-1 TIM record began Jan 11, 2018. ClimateExplorer uses the satellite-based observed TSI record, which begins in 1978.
Global temperature anomaly
The NOAA Merged Land Ocean Global Surface Temperature Analysis (NOAAGlobalTemp, formerly known as MLOST) combines long-term sea surface (water) temperature (SST) and land surface (air) temperature datasets to create a complete, accurate depiction of global temperature trends. The dataset is used to support climate monitoring activities such as the Monthly Global Climate Assessment, and also provides input data for a number of climate models.
The reference period used to calculate the anomalies is 1971–2000.
The Laboratory for Satellite Altimetry (LSA), part of the Center for Satellite Applications and Research (STAR), specializes in the application of satellite altimetry to a broad array of climate and weather related issues, including global and regional sea level rise, coastal and open-ocean circulation, weather prediction and monitoring the changing state of the Arctic Ocean.
Mean sea level
Data are from TOPEX/Poseidon (T/P), Jason-1, Jason-2, and Jason-3, which have monitored the same ground track since 1992.
Only altimetry measurements between 66°S and 66°N have been processed. An inverted barometer has been applied to the time series. The estimates of sea level rise do not include glacial isostatic adjustment effects on the geoid, which are modeled to be +0.2 to +0.5 mm/year when globally averaged.
The Global Carbon Project
The Global Carbon Project (GCP) integrates knowledge of greenhouse gases for human activities and the Earth system. Their projects include global budgets for three dominant greenhouse gases — carbon dioxide, methane, and nitrous oxide — and complementary efforts in urban, regional, cumulative, and negative emissions.
Carbon dioxide emissions
The Global Carbon Project (GCP) has been publishing estimates of global and national fossil CO₂ emissions since 2001. In the first instance these were simple re-publications of data from another source, but over subsequent years refinements have been made in response to feedback and identification of inaccuracies.
Copernicus Atmospheric Monitoring Service (CAMS)
Copernicus is the Earth observation component of the European Union's Space programme, looking at our planet and its environment.
Southern Hemisphere ozone hole area
During the Southern Hemisphere spring season (August - October) the ozone hole over the Antarctic increases in size, reaching a maximum between mid-September and mid-October.
When temperatures high up in the atmosphere (stratosphere) start to rise in late Southern Hemisphere spring, ozone depletion slows, the polar vortex weakens and finally breaks down, and by the end of December ozone levels have returned to normal.
The ozone hole area is calculated as the area with ozone values below 220 DU south of 60S.
Southern Hemisphere ozone column
Ozone values are often measured as the number of ozone molecules in a vertical column and denoted in Dobson Units (DU). During the Antarctic ozone hole period, values can be less than half the normal levels. CAMS monitors the minimum value within the ozone hole area over time as another measure of the significance of each year's event. By comparing the current state of the ozone hole with its long-term evolution, it is possible to get an indication of whether the ozone layer is being restored and how fast this process is occurring, bearing in mind that meteorological and dynamical interannual variability also impact the size and duration of the current ozone hole.
National Snow & Ice Data Center (NSIDC)
Arctic sea ice extent
The daily Sea Ice Index provides a quick look at Arctic-wide changes in sea ice. It provides consistently processed daily ice extent and concentration images and data since 1979.
Antarctic sea ice extent
The daily Sea Ice Index provides a quick look at Antarctic-wide changes in sea ice. It provides consistently processed daily ice extent and concentration images and data since 1979.
Greenland ice melt area
Greenland ice melt area since 1979
Met Office
Hadley Centre Central England Temperature
The Hadley Centre Central England Temperature (HadCET) dataset provides daily and monthly mean, minimum and maximum temperatures representative of a roughly triangular area enclosed by Lancashire, London and Bristol.
The monthly mean series begins in 1659 and is the longest instrumental temperature record in the world, while daily mean temperatures begin in 1772 and minimum and maximum temperature series begin in 1878.
The precipitation record is drawn from the UK regional precipitation series (HadUKP), which incorporates the long-running England & Wales Precipitation (EWP) series beginning in 1766, the longest instrumental series of its kind in the world. ClimateExplorer uses HadCEP (Central England precipitation), a daily series that begins in 1931.
Royal Observatory of Belgium
Sunspot number
Sunspot number since 1818, published via the World Data Center for Sunspot Index and Long-term Solar Observations (WDC-SILSO). On July 1st, 2015, the sunspot number series has been replaced by a new improved version (version 2.0) that includes several corrections of past inhomogeneities in the time series.
