Köppen Climate Classification Calculator

Enter monthly temperature and precipitation to determine the Köppen climate type for any location, then explore what that code means.

Climate science Köppen–Geiger Interactive calculator

Köppen Climate Calculator

Use positive for N, negative for S. Used for dry-climate threshold.

Precipitation units
Month Temp (°C) Precip

What is the Köppen climate classification?

The Köppen climate classification (often called Köppen–Geiger) is one of the most widely used systems for describing world climates. It groups climates based on long‑term averages of temperature and precipitation, and how these vary through the year.

Each climate type is written as a short code such as Af, BWh, or Cfb. The first letter describes the main climate group, the second letter describes precipitation pattern, and the third letter (if present) refines the temperature regime.

Main Köppen climate groups

Group Name Key criteria (simplified)
A Tropical All months ≥ 18 °C; high precipitation, no cold season.
B Dry (arid & semi‑arid) Annual precipitation < threshold Pth based on temperature and seasonality.
C Temperate (mesothermal) Coldest month between 0 and 18 °C; at least one month > 10 °C.
D Continental (microthermal) Coldest month ≤ 0 °C; at least one month > 10 °C.
E Polar Warmest month < 10 °C.

Dry-climate threshold (group B)

To decide whether a location is a dry climate (group B), Köppen compares annual precipitation P with a threshold Pth that depends on annual mean temperature and whether precipitation is concentrated in summer or winter.

Step 1 – Compute base threshold:

\( P_{base} = 20 \times T_{mean} \)

Step 2 – Adjust for seasonality:

  • If ≥ 70% of precipitation falls in the summer half-year (Apr–Sep in N hemisphere, Oct–Mar in S): \( P_{th} = P_{base} + 280 \)
  • If ≥ 70% falls in the winter half-year: \( P_{th} = P_{base} \)
  • Otherwise (no strong seasonality): \( P_{th} = P_{base} + 140 \)

Step 3 – Compare with annual precipitation P:

  • If \( P < 0.5 \, P_{th} \) → BW (desert)
  • If \( 0.5 \, P_{th} \le P < P_{th} \) → BS (steppe)

Second and third letters

  • Precipitation letters (second letter):
    • f – no dry season (“fully humid”)
    • s – dry summer
    • w – dry winter
    • W/S – desert/steppe (for group B)
  • Temperature letters (third letter):
    • h – hot (mean annual T ≥ 18 °C, for B climates)
    • k – cold (mean annual T < 18 °C, for B climates)
    • a – hot summer (warmest month ≥ 22 °C)
    • b – warm summer (warmest month < 22 °C, ≥ 4 months > 10 °C)
    • c – cool summer (1–3 months > 10 °C)
    • d – very cold winter (for some D climates; coldest month ≤ −38 °C)
    • T – tundra (for ET)
    • F – frost/ice cap (for EF)

Examples of common Köppen climate types

Code Name Typical regions
Af Tropical rainforest Amazon Basin, Congo Basin, parts of Southeast Asia.
Aw/As Tropical savanna Sahel, parts of India, cerrado of Brazil.
BWh Hot desert Sahara, Arabian Peninsula, central Australia.
BSk Cold semi‑arid steppe Great Plains (US), parts of Central Asia.
Csa Hot‑summer Mediterranean Coastal California, Mediterranean Basin, parts of Chile.
Cfb Temperate oceanic Western Europe, New Zealand, coastal Pacific Northwest.
Dfb Humid continental Eastern Europe, southern Canada, northern US Midwest.
ET / EF Tundra / Ice cap Arctic and Antarctic regions, high mountains.

How this calculator works (algorithm overview)

  1. Convert units – If you enter precipitation in inches, the tool converts to millimeters.
  2. Compute statistics – Annual mean temperature, annual precipitation, warmest and coldest month, number of months above 10 °C and below 0 °C, and seasonal precipitation (summer vs. winter half‑year).
  3. Check for polar climates (E) – If the warmest month is < 10 °C, classify as ET or EF.
  4. Check for dry climates (B) – Compute the dry‑climate threshold Pth and compare with annual precipitation to decide BW vs. BS, then h vs. k.
  5. Assign temperate (C) vs. continental (D) – Based on the coldest month temperature and number of months > 10 °C.
  6. Determine precipitation letter – Identify dry summer (s), dry winter (w), or fully humid (f) using monthly precipitation ratios.
  7. Determine temperature letter – Use warmest month temperature and number of months > 10 °C to assign a, b, c, or d.

Limitations and good practice

  • Use 30‑year climate normals (e.g., 1991–2020) for best results, not a single year.
  • Local microclimates (urban heat islands, mountain valleys) may differ from coarse global maps.
  • Different authors use slightly different thresholds; this tool follows a commonly used Köppen–Geiger variant.

FAQ

Can I classify future or past climates?

Yes. If you have monthly temperature and precipitation projections (for example, from climate models) or historical reconstructions, you can enter them here to see how the Köppen type would change. Just make sure the data represent a multi‑decadal average.

Why do my results differ from some online maps?

Published Köppen–Geiger maps (such as those from research groups or national agencies) are based on specific datasets and interpolation methods. Small differences in input data, period, or exact thresholds can shift a location from one subtype to another, especially near boundaries.

Is Köppen the only climate classification?

No. Other systems include the Thornthwaite classification, Holdridge life zones, and various agro‑climatic schemes. Köppen remains popular because it is simple, reproducible, and closely linked to vegetation patterns.