Cambodia weather 2021–2026: what the data shows, and what may come next

Sources: camweather.info's own history data (ERA5 grid, CAMS air, IBTrACS storms, river gauges, climate indices). 2026 runs to 18–23 October only, so its totals are not full years. Every number below has been re-checked, and claims the checks disputed have been removed.


1) The last 5 years at a glance

Rain (country average, mm)

2021 2022 2023 2024 2025 2026 so far
Full year 1769 2144 (wettest) 1931 1723 1889 –
1 Jan–18 Oct 1516 1928 1711 1534 1624 1541 (4th of 7)
Rainy season began 18 Apr 16 Mar 12 Apr 9 May (late) 8 Apr 13 May (late)

Heat

2021 2022 2023 2024 2025 2026 so far
Average daily high, 1 Jan–18 Oct (°C) 31.9 31.7 32.1 33.0 31.9 32.4 (2nd hottest)
Year vs normal (°C) −0.10 −0.06 +0.33 +0.89 (record) −0.09 +0.28 (Jan–Sep)
Hottest day (°C) 41.1 41.2 42.3 43.8 40.4 42.8

Rivers (highest level of the year, m)

2021 2022 2023 2024 2025 2026
Phnom Penh 6.58 7.84 6.87 7.73 8.16 7.98
Kratie 18.51 20.54 20.05 21.64 21.66 21.88 (23 Aug, early)
Flood days, any station 0 0 0 0 0 0

Storms (South China Sea or within 800 km)

2021 2022 2023 2024 2025 2026 so far
Systems 14 10 7 12 19 5
Within 500 km of Cambodia 3 3 1 3 1 (Kalmaegi, 80 kt) 0

Air (smoke/haze, PM2.5) and sea

2021 2022 2023 2024 2025 2026 so far
Worst month, average (µg/m³) – – 25.7 (Apr) 21.4 (Mar) 30.6 (Apr) 32 (Apr)
Unhealthy days, country average – – 5–6 0 22 about 5–9
Rough-sea days (waves ≥2 m) 10 15 18 20 15 2 (to 18 Oct)

El Niño / La Niña

2021 2022 2023 2024 2025 2026
La Niña La Niña El Niño (strong by year end) El Niño fading Neutral, then weak La Niña Very strong El Niño, still growing

2) What changed


3) What may happen next

Coming weeks (late Oct–Nov 2026)

Dry season, Nov 2026–Apr 2027

2027 rainy season

Re-check all of this with the spring 2027 forecasts.


4) What the website should do about it

  1. Heat Watch, March–May (top priority). Add a daily heat card with "feels-like" and the maximum by province, with the north-west first. Raise alerts at 38 °C and 40 °C and at heat index 41 °C. Show a "Hot season outlook" banner from February when the seasonal forecast is above +1.5 °C.
  2. Haze Season warning, January–May. Show a daily PM2.5 card per province using colour bands, with an alert above 35.4 µg/m³ for sensitive groups (Phnom Penh/Kandal, Takeo, Svay Rieng, Prey Veng, Pursat). Add simple advice: masks, children, outdoor work.
  3. Low River / Dry Season Water page. Compare today's level with the same date in past years ("2nd lowest in 25 years"). Show the trend towards the end of the year and the 2015/2019 record lows. This is useful for farmers and fisheries.
  4. El Niño status card. Show the current state in plain words ("Strong El Niño: expect a hotter, drier dry season"), with a link to the outlook.
  5. Rainy-season start and end tracker. Show "Has the rainy season started/ended?" by our rule, and the date compared with past years. In March–April, add a "Dry April – late start possible" note for farmers.
  6. Late-season Storm Watch, Oct–Dec. Add a card when any system enters the South China Sea, with its distance from Cambodia and the expected rain, not just the wind.
  7. Rough-sea alert, Nov–Feb. Warn coastal provinces (Koh Kong, Preah Sihanouk, Kampot, Kep) when waves of 2 m or more are forecast.
  8. "This year vs past years" page for management. Put these tables on the existing dashboard and update them automatically each month.

Limits: Most numbers are grid data (ERA5 and CAMS models), not gauges, so real local extremes are higher. Storm and haze outlooks are based on only 4–7 past years. Forecasts more than 3 months ahead are guidance, not certainty.

Worked out on 24 October 2026 from camweather.info's own history (ERA5 and CAMS grids, IBTrACS storms, MRC rivers, climate indices); every number re-checked by a second analysis. See also Prediction and Rain chances.