September in San Bernardino brings high temperatures around 28°C (82°F) during the day, dropping to 16°C (61°F) at night, with quite a bit of rainfall expected, averaging around 121 mm (4.8 in) for the month.
If you prefer dry days with pleasant temperatures, July and August typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
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Pick a month to see the average temperature, rainfall and sunshine in San Bernardino - and find the best time to visit.
50-year average (1976-2025)
Based on our historical records, temperatures in San Bernardino typically stay consistent throughout September, with daily highs averaging around 28°C (82°F). Nights are pleasant, with lows typically ranging from 15°C (59°F) to 18°C (64°F).
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Browse day-by-day weather records for San Bernardino spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
The extremes listed below come from historical weather data collected in San Bernardino from 1976 through 2026.
Find out more about the weather in Paraguay and which places have the best travel conditions in this month. See all of Paraguay in September →
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Warm temperatures in September make for comfortable sightseeing weather. Pack breathable fabrics like cotton shirts, knee-length shorts or skirts, and comfortable walking shoes. A thin long sleeve for indoor spaces is handy. Prepare for significant rainfall with proper waterproof clothing and shoes. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Temperature Rainfall Sunshine Humidity
See the full San Bernardino climate overview or explore weather in Paraguay.
Where to go in September - average daytime high across popular destinations.
San Bernardino
28°C (82°F) Areguá28°C (82°F) Asuncion29°C (84°F) Luque28°C (82°F) Ybycuí
27°C (81°F) Villarrica28°C (82°F) Ciudad del Este
28°C (82°F) Encarnación26°C (79°F) Need travel inspiration? Check out our bucket list articles and be inspired.
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