San Bernardino Weather in September
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.
Rainfall in San Bernardino in September
Records from the past 30 years suggest around 5 days of rain, with 121 mm (4.8 in) average for the month. Rainfall tends to arrive in short, intense showers this month. Rain days are few, but the showers can be surprisingly heavy.
Temperature in San Bernardino in September
If you're visiting San Bernardino in September, expect highs of 28°C (82°F) and overnight lows around 16°C (61°F). Conditions stay fairly consistent through the month, making it easier to plan what to wear. With overnight lows of 16°C (61°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep.
Sunshine in San Bernardino in September
The days are predominantly sunny, with an estimated total of around 203 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.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.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Paraguay, check out our San Bernardino's climate page.
San Bernardino Temperature in September
Min Temperature
16°C (61°F)
Max Temperature
28°C (82°F)
Chance of Rain
18%
Precipitation
121 mm (4.8 in)
Rainy days
5 days
Humidity
65% *
Sunshine
203 hours *
Percentage Sunshine
*
Daily Historical Temperatures
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).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for San Bernardino in September
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.
San Bernardino historical weather extremes in September
The extremes listed below come from historical weather data collected in San Bernardino from 1976 through 2025.
- San Bernardino recorded its highest September temperature of 42°C (108°F) on September 26, 2020.
- San Bernardino registered its coldest September night on September 6, 2006, with temperatures dropping to 3°C (37°F).
Best Places in Paraguay in September
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
pleasant
tolerable
unpleasant
poor
What to Wear in San Bernardino in September
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.What To Do in San Bernardino in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Paraguay, check out our San Bernardino's climate page.
Temperature Rainfall Sunshine Humidity
See the full San Bernardino climate overview or explore weather in Paraguay.
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