Iguazu Falls · Month comparison

September vs May

May ranks #1 overall vs September at #4. Shoulder month: pleasantly cool (23C/13C), 30% off summer hotel rates, river flow tapering but still strong.

September Iguazu Falls Argentine side with returning spring vegetation

September

#4 of 12 months

Best match

Spring rains return and water levels start rebuilding — strong shoulder month with low crowds.

  • ↑Quietest month of the year before holiday crowds rebuild
  • ↑Spring flush — water gradually rises while temps stay pleasant
May cooler-light Iguazu Falls Devil's Throat from above

May

#1 of 12 months

Best match

Shoulder month: pleasantly cool (23C/13C), 30% off summer hotel rates, river flow tapering but still strong.

  • ↑Hotel Loi Suites Iguazu from USD 180 vs USD 280+ in January
  • ↑Argentine Park Upper Trail cool enough for full-day walking
FactorSeptemberMay
Weather score
8
8
Value score
7
8
Crowd score
7
7
Events score
4
4
Atmosphere
8
8
Avg high temp26°C23°C
Monthly rain130mm110mm
Daily sunshine6.5hrs6hrs

September trade-offs

  • ↓Mosquitoes return with the rains
  • ↓Rain showers more frequent late afternoon
  • ↓Brazilian-side helicopter sometimes cancelled on storms

May trade-offs

  • ↓Evenings can drop to 10C — bring layers
  • ↓Some cataracts already visibly thinning vs Feb
  • ↓Boat tours (Macuco) suspend on cold/cloudy days
See all 12 months for Iguazu Falls →September in detail →May in detail →
Scores compare months within Iguazu Falls. Climate data: Open Meteo ERA5 30-year normals (1991–2020). Methodology →