Interpreting an estimated Köppen–Geiger climate class
The Köppen–Geiger system groups climates using temperature, precipitation, and precipitation seasonality. This calculator applies a simplified decision tree to twelve monthly mean temperatures and precipitation totals.
Use long-term climate normals rather than one unusual year. Published classifications may use a specific Köppen–Geiger variant, gridded observations, quality controls, and spatial interpretation that this screening tool does not reproduce.
How to use the climate zone calculator
- Select the hemisphere: This determines which six-month period the tool treats as summer.
- Enter temperatures: Provide all twelve long-term monthly mean temperatures in degrees Celsius.
- Enter precipitation: Provide all twelve long-term monthly precipitation totals in millimeters.
- Classify and verify: Treat the result as a screening class and compare it with a recognized map or full classification method.
Formula and variables
Threshold tests identify tropical, arid, temperate, continental, or polar groups and then estimate precipitation and temperature subclasses.
Class = f(monthly temperature, monthly precipitation, hemisphere)- Tᵢ — Monthly temperature
- Mean temperature for month i (°C)
- Pᵢ — Monthly precipitation
- Total precipitation for month i (mm)
- Pannual — Annual precipitation
- Sum of all twelve monthly totals (mm)
Northern Hemisphere example
A site has mild wet winters, warm dry summers, and the default twelve-month dataset shown in the calculator.
- Hemisphere
- Northern
- Temperature range
- 5–21 °C
- Annual precipitation
- 920 mm
- Identify the broad thermal group
- Compare summer and winter precipitation thresholds
- Apply the summer-temperature subclass
Result: The screening result is Csb, a warm-summer Mediterranean-type climate.
A published dataset may classify a boundary location differently because of period, resolution, and classification variant.
Understanding your results
Read the letters as threshold categories
The first letter is the broad climate group; later letters summarize moisture seasonality and temperature.
- A classes are tropical, B arid, C temperate, D continental, and E polar.
- A class is descriptive, not a weather forecast.
- Small input changes can switch a site near a threshold.
Assumptions
- Inputs are representative long-term monthly climatologies.
- Temperature uses degrees Celsius and precipitation uses millimeters.
- Six-month seasonal groupings adequately represent the selected hemisphere.
Limitations
- Implements a simplified subset of Köppen–Geiger thresholds and names.
- Does not classify highland climate separately or resolve every D-climate subclass.
- Does not fetch location data, assess data quality, interpolate terrain, or quantify classification confidence.
- Not a building-code, agricultural-hardiness, or HVAC climate-zone lookup.
Common mistakes
- Entering daily or annual averages instead of twelve monthly values.
- Using Fahrenheit or inches without conversion.
- Selecting the wrong hemisphere.
- Treating one year of weather as a climate normal.
- Confusing Köppen climate classes with construction energy-code zones.
Practical use cases
Climate education
Explore how thermal and seasonal precipitation thresholds affect a climate label.
Dataset screening
Generate a preliminary class for monthly climatology before consulting a published map.
Frequently asked questions
Is this the same as an IECC or ASHRAE climate zone?
No. This tool estimates a Köppen–Geiger climate type; construction and energy standards use different zone systems.
Should I use one year or a long-term average?
Use a quality-controlled long-term monthly climatology. A single year can be anomalous.
Why can another map show a different class?
Classification variant, averaging period, station quality, grid resolution, topography, and borderline thresholds can change the result.
Sources and review
- Updated world map of the Köppen-Geiger climate classification — Hydrology and Earth System Sciences. Accessed 2026-07-13.
- Present and future Köppen-Geiger climate classification maps at 1-km resolution — Scientific Data. Accessed 2026-07-13.
Reviewed 2026-07-13.