Dec
Dustiest month
12
Episodes per year
18 days
Longest episode observed
Share of days with dust above the EU limit
Bar chart of the share of days each month with daily mean PM10 above the EU limit value. Exact figures are in the table below.
Show the month-by-month numbers
| Month | Over EU limit | Noticeable dust | Heavy dust | Worst 10% of days |
|---|---|---|---|---|
| January | 19% | 26% | 10% | 120 µg/m³ |
| February | 20% | 27% | 12% | 130 µg/m³ |
| March | 1% | 1% | 0% | 19 µg/m³ |
| April | 8% | 10% | 0% | 37 µg/m³ |
| May | 0% | 0% | 0% | 18 µg/m³ |
| June | 0% | 1% | 0% | 22 µg/m³ |
| July | 2% | 2% | 0% | 27 µg/m³ |
| August | 12% | 18% | 0% | 56 µg/m³ |
| September | 7% | 8% | 1% | 31 µg/m³ |
| October | 9% | 14% | 3% | 38 µg/m³ |
| November | 14% | 19% | 2% | 88 µg/m³ |
| December | 30% | 40% | 11% | 126 µg/m³ |
“Noticeable” = daily mean Saharan dust over 50 µg/m³, “heavy” = over 200. The first column uses the EU daily limit of 50 µg/m³, a health standard rather than a visibility one — a day can cross it and still look merely hazy.
Compare the zones
| Zone | Episodes / year | Typical length | Longest |
|---|---|---|---|
| South resorts (Costa Adeje / Los Cristianos) | 12 | 2 days | 18 days |
| Rest of the island (north, capital, summit) | 9.7 | 2 days | 17 days |
Only two areas are listed, not four. The CAMS model grid is coarser than Tenerife: the north coast, Santa Cruz and the summit all fall in the same cell and return identical values, so they are shown merged. This data cannot tell you whether the summit differs from the coast.
Three things worth knowing
It is not a summer thing
The story everyone repeats is that calima comes with the August heat. In this record the worst month on the south coast is December. August is real, but it is not the peak — summer dust rides in high and hot, which is why it is memorable, while winter dust sits low on the coast, which is what a ground-level health measurement picks up.
The average episode is fine. The tail is not.
A typical episode lasts 2 days — an annoyance you wait out. The longest in the record lasted 18. That asymmetry is the whole practical point: plan for the median, and know the tail exists.
Only 3 years behind this
The dust dataset starts in late 2022, so every monthly figure rests on 3 samples of that month. Trust the ranking of months; treat the exact percentages as provisional. Saying so is cheaper than being wrong quietly.