Lima weather in September

Regulars name a specific local phenomenon, the garua, as the defining feature of this month - a damp, cold, low-lying maritime mist that hangs over the city and makes surfaces genuinely slippery, all without producing anything that counts as real rain. Our row backs that grey, misty read, 20.6C over 16.5C nights, with essentially no measurable rain, 1.4mm and zero rainy days recorded, alongside humidity at 77 percent, consistent with mist rather than rainfall driving the dampness. Regulars are consistent temperatures rarely climb above 20C for the full stretch this typically continues, a genuinely different Lima than the sunny coastal city many expect. A proper waterproof jacket is the standard advice despite the near-total absence of actual rain. The record: 10.6 hours of sun, a 12.7 kph wind and AQI 47.

Regulars are specific that the city's famous garua, the thick grey mist that hangs over Lima for much of the second half of the year, hasn't properly settled in by this point - visitors report going a full trip in mid-May without seeing it at all, since the fog's main season runs June through December instead. Our row backs a still-mild, largely dry month, 22.9C reading as 25C, over 17.8C nights, with rain nearly absent at 2.8mm across under a day - Lima's coastal desert climate produces almost none of its own rain even at the wettest point of the year. Humidity stays notably high, 82 percent, even without the visible mist, a preview of the damp grey stretch still to come. The sea sits at 22.3C. The record: 10.5 hours of sun, a 12.5 kph wind and AQI 46.

Lima earns its nickname, la Gris, from the garua - the cold damp mist that sits over the city for much of the year - and October is the month it lets go. Regulars say the early part can still be overcast and the later part brightens, with winter effectively gone by September and October and November warm and bright without being hot, around 16 to 23C. Our row lands inside that at 21.7C over 16.7C, with 11.4 hours of sun and rain that is barely there at 4mm across 1.2 days. Humidity stays at 79 percent all the same, which is the point about this coast: the moisture arrives as mist, not as rain. The record: a 13.4 kph wind, an 18.5C sea and AQI 39.

November is when Lima starts to come out from under the garua - the thick grey coastal fog that sits over the city from about June to December - and regulars describe blue skies, brighter days, lower humidity and pleasant temperatures arriving now, with late-November visitors usually lucky and occasionally still greyed out. The clear run is December to April. Our row gives 23C days over 17.9C nights at 79 percent humidity, and almost nothing falling: 3.4mm across 0.8 precipitation days, because the garua is fog rather than rain and our dataset cannot see it. The sea stays cold at 18.7C. The record: feels-like 25C, 11.4 hours of sun and AQI 43.