United States Rancho Cucamonga, California
Long Range Weather Forecast

Helping You Avoid Bad Weather. 30 days and beyond.

Rancho Cucamonga, September 2025 Weather Forecast: A Day-by-Day Calendar View Rancho Cucamonga Weather Outlook: Detailed September 2025 Calendar Sun Mon Tue Wed Thu Fri Sat 1 89°F 55°F 32°C 13°C 13% Rancho Cucamonga weather forecast for Sep 1, 2025: 13% Rain Chance, Highs/Lows 89°F to ?89°F Rancho Cucamonga weather forecast for Sep 1, 2025: 13% Rain Chance, Highs/Lows 32°C to ?32°C 2 90°F 55°F 32°C 13°C 04% Rancho Cucamonga weather forecast for Sep 2, 2025: 4% Rain Chance, Highs/Lows 90°F to ?90°F Rancho Cucamonga weather forecast for Sep 2, 2025: 4% Rain Chance, Highs/Lows 32°C to ?32°C 3 89°F 56°F 32°C 13°C 05% Rancho Cucamonga weather forecast for Sep 3, 2025: 5% Rain Chance, Highs/Lows 89°F to ?89°F Rancho Cucamonga weather forecast for Sep 3, 2025: 5% Rain Chance, Highs/Lows 32°C to ?32°C 4 88°F 57°F 31°C 14°C 04% Rancho Cucamonga weather forecast for Sep 4, 2025: 4% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 4, 2025: 4% Rain Chance, Highs/Lows 31°C to ?31°C 5 88°F 55°F 31°C 13°C 05% Rancho Cucamonga weather forecast for Sep 5, 2025: 5% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 5, 2025: 5% Rain Chance, Highs/Lows 31°C to ?31°C 6 88°F 56°F 31°C 13°C 04% Rancho Cucamonga weather forecast for Sep 6, 2025: 4% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 6, 2025: 4% Rain Chance, Highs/Lows 31°C to ?31°C 7 89°F 56°F 32°C 13°C 12% Rancho Cucamonga weather forecast for Sep 7, 2025: 12% Rain Chance, Highs/Lows 89°F to ?89°F Rancho Cucamonga weather forecast for Sep 7, 2025: 12% Rain Chance, Highs/Lows 32°C to ?32°C 8 88°F 56°F 31°C 13°C 05% Rancho Cucamonga weather forecast for Sep 8, 2025: 5% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 8, 2025: 5% Rain Chance, Highs/Lows 31°C to ?31°C 9 88°F 55°F 31°C 13°C 06% Rancho Cucamonga weather forecast for Sep 9, 2025: 6% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 9, 2025: 6% Rain Chance, Highs/Lows 31°C to ?31°C 10 88°F 55°F 31°C 13°C 05% Rancho Cucamonga weather forecast for Sep 10, 2025: 5% Rain Chance, Highs/Lows 88°F to ?88°F Rancho Cucamonga weather forecast for Sep 10, 2025: 5% Rain Chance, Highs/Lows 31°C to ?31°C 11 86°F 55°F 30°C 13°C 08% Rancho Cucamonga weather forecast for Sep 11, 2025: 8% Rain Chance, Highs/Lows 86°F to ?86°F Rancho Cucamonga weather forecast for Sep 11, 2025: 8% Rain Chance, Highs/Lows 30°C to ?30°C 12 86°F 55°F 30°C 13°C 09% Rancho Cucamonga weather forecast for Sep 12, 2025: 9% Rain Chance, Highs/Lows 86°F to ?86°F Rancho Cucamonga weather forecast for Sep 12, 2025: 9% Rain Chance, Highs/Lows 30°C to ?30°C 13 86°F 54°F 30°C 12°C 05% Rancho Cucamonga weather forecast for Sep 13, 2025: 5% Rain Chance, Highs/Lows 86°F to ?86°F Rancho Cucamonga weather forecast for Sep 13, 2025: 5% Rain Chance, Highs/Lows 30°C to ?30°C 14 84°F 55°F 29°C 13°C 04% Rancho Cucamonga weather forecast for Sep 14, 2025: 4% Rain Chance, Highs/Lows 84°F to ?84°F Rancho Cucamonga weather forecast for Sep 14, 2025: 4% Rain Chance, Highs/Lows 29°C to ?29°C 15 83°F 56°F 28°C 13°C 21% Rancho Cucamonga weather forecast for Sep 15, 2025: 21% Rain Chance, Highs/Lows 83°F to ?83°F Rancho Cucamonga weather forecast for Sep 15, 2025: 21% Rain Chance, Highs/Lows 28°C to ?28°C 16 84°F 54°F 29°C 12°C 17% Rancho Cucamonga weather forecast for Sep 16, 2025: 17% Rain Chance, Highs/Lows 84°F to ?84°F Rancho Cucamonga weather forecast for Sep 16, 2025: 17% Rain Chance, Highs/Lows 29°C to ?29°C 17 84°F 53°F 29°C 12°C 06% Rancho Cucamonga weather forecast for Sep 17, 2025: 6% Rain Chance, Highs/Lows 84°F to ?84°F Rancho Cucamonga weather forecast for Sep 17, 2025: 6% Rain Chance, Highs/Lows 29°C to ?29°C 18 85°F 52°F 29°C 11°C 06% Rancho Cucamonga weather forecast for Sep 18, 2025: 6% Rain Chance, Highs/Lows 85°F to ?85°F Rancho Cucamonga weather forecast for Sep 18, 2025: 6% Rain Chance, Highs/Lows 29°C to ?29°C 19 85°F 52°F 29°C 11°C 08% Rancho Cucamonga weather forecast for Sep 19, 2025: 8% Rain Chance, Highs/Lows 85°F to ?85°F Rancho Cucamonga weather forecast for Sep 19, 2025: 8% Rain Chance, Highs/Lows 29°C to ?29°C 20 85°F 52°F 29°C 11°C 08% Rancho Cucamonga weather forecast for Sep 20, 2025: 8% Rain Chance, Highs/Lows 85°F to ?85°F Rancho Cucamonga weather forecast for Sep 20, 2025: 8% Rain Chance, Highs/Lows 29°C to ?29°C 21 86°F 53°F 30°C 12°C 04% Rancho Cucamonga weather forecast for Sep 21, 2025: 4% Rain Chance, Highs/Lows 86°F to ?86°F Rancho Cucamonga weather forecast for Sep 21, 2025: 4% Rain Chance, Highs/Lows 30°C to ?30°C 22 85°F 53°F 29°C 12°C 13% Rancho Cucamonga weather forecast for Sep 22, 2025: 13% Rain Chance, Highs/Lows 85°F to ?85°F Rancho Cucamonga weather forecast for Sep 22, 2025: 13% Rain Chance, Highs/Lows 29°C to ?29°C 23 82°F 54°F 28°C 12°C 08% Rancho Cucamonga weather forecast for Sep 23, 2025: 8% Rain Chance, Highs/Lows 82°F to ?82°F Rancho Cucamonga weather forecast for Sep 23, 2025: 8% Rain Chance, Highs/Lows 28°C to ?28°C 24 81°F 52°F 27°C 11°C 08% Rancho Cucamonga weather forecast for Sep 24, 2025: 8% Rain Chance, Highs/Lows 81°F to ?81°F Rancho Cucamonga weather forecast for Sep 24, 2025: 8% Rain Chance, Highs/Lows 27°C to ?27°C 25 81°F 53°F 27°C 12°C 04% Rancho Cucamonga weather forecast for Sep 25, 2025: 4% Rain Chance, Highs/Lows 81°F to ?81°F Rancho Cucamonga weather forecast for Sep 25, 2025: 4% Rain Chance, Highs/Lows 27°C to ?27°C 26 82°F 52°F 28°C 11°C 13% Rancho Cucamonga weather forecast for Sep 26, 2025: 13% Rain Chance, Highs/Lows 82°F to ?82°F Rancho Cucamonga weather forecast for Sep 26, 2025: 13% Rain Chance, Highs/Lows 28°C to ?28°C 27 82°F 53°F 28°C 12°C 08% Rancho Cucamonga weather forecast for Sep 27, 2025: 8% Rain Chance, Highs/Lows 82°F to ?82°F Rancho Cucamonga weather forecast for Sep 27, 2025: 8% Rain Chance, Highs/Lows 28°C to ?28°C 28 83°F 54°F 28°C 12°C 17% Rancho Cucamonga weather forecast for Sep 28, 2025: 17% Rain Chance, Highs/Lows 83°F to ?83°F Rancho Cucamonga weather forecast for Sep 28, 2025: 17% Rain Chance, Highs/Lows 28°C to ?28°C 29 83°F 54°F 28°C 12°C 27% Rancho Cucamonga weather forecast for Sep 29, 2025: 27% Rain Chance, Highs/Lows 83°F to ?83°F Rancho Cucamonga weather forecast for Sep 29, 2025: 27% Rain Chance, Highs/Lows 28°C to ?28°C 30 83°F 53°F 28°C 12°C 05% Rancho Cucamonga weather forecast for Sep 30, 2025: 5% Rain Chance, Highs/Lows 83°F to ?83°F Rancho Cucamonga weather forecast for Sep 30, 2025: 5% Rain Chance, Highs/Lows 28°C to ?28°C

Weather Forecast Legend

WeatherTAB helps you plan activities on days with the least risk of rain.
Low risk of rain/snow.
Transition Day – Start or End of a Risky Period
Medium risk of rain/snow.
High risk of rain/snow.
%
Forecast risk of rain/snow.
Rancho Cucamonga Weather Forecast for Sep 2025 - Risk of Rain Graph ) Rancho Cucamonga Weather Forecast for Sep 2025 - Risk of Rain Graph 90 80 70 60 50 40 30 20 10 Sep 1: Precipitation Risk Forecast - 13% risk of rain/snow. /n1 M Sep 2: Precipitation Risk Forecast - 04% risk of rain/snow. /n2 T Sep 3: Precipitation Risk Forecast - 05% risk of rain/snow. /n3 W Sep 4: Precipitation Risk Forecast - 04% risk of rain/snow. /n4 Th Sep 5: Precipitation Risk Forecast - 05% risk of rain/snow. /n5 F Sep 6: Precipitation Risk Forecast - 04% risk of rain/snow. /n6 S Sep 7: Precipitation Risk Forecast - 12% risk of rain/snow. /n7 Sn Sep 8: Precipitation Risk Forecast - 05% risk of rain/snow. /n8 M Sep 9: Precipitation Risk Forecast - 06% risk of rain/snow. /n9 T Sep 10: Precipitation Risk Forecast - 05% risk of rain/snow. /n10 W Sep 11: Precipitation Risk Forecast - 08% risk of rain/snow. /n11 Th Sep 12: Precipitation Risk Forecast - 09% risk of rain/snow. /n12 F Sep 13: Precipitation Risk Forecast - 05% risk of rain/snow. /n13 S Sep 14: Precipitation Risk Forecast - 04% risk of rain/snow. /n14 Sn Sep 15: Precipitation Risk Forecast - 21% risk of rain/snow. /n15 M Sep 16: Precipitation Risk Forecast - 17% risk of rain/snow. /n16 T Sep 17: Precipitation Risk Forecast - 06% risk of rain/snow. /n17 W Sep 18: Precipitation Risk Forecast - 06% risk of rain/snow. /n18 Th Sep 19: Precipitation Risk Forecast - 08% risk of rain/snow. /n19 F Sep 20: Precipitation Risk Forecast - 08% risk of rain/snow. /n20 S Sep 21: Precipitation Risk Forecast - 04% risk of rain/snow. /n21 Sn Sep 22: Precipitation Risk Forecast - 13% risk of rain/snow. /n22 M Sep 23: Precipitation Risk Forecast - 08% risk of rain/snow. /n23 T Sep 24: Precipitation Risk Forecast - 08% risk of rain/snow. /n24 W Sep 25: Precipitation Risk Forecast - 04% risk of rain/snow. /n25 Th Sep 26: Precipitation Risk Forecast - 13% risk of rain/snow. /n26 F Sep 27: Precipitation Risk Forecast - 08% risk of rain/snow. /n27 S Sep 28: Precipitation Risk Forecast - 17% risk of rain/snow. /n28 Sn Sep 29: Precipitation Risk Forecast - 27% risk of rain/snow. /n29 M Sep 30: Precipitation Risk Forecast - 05% risk of rain/snow. /n30 T

Rain Risk Graph: Monthly Overview. Bar heights indicate rain risk percentages. Yellow bars mark low-risk days, while black and grey bars signal higher risks. Grey-yellow bars act as buffers, advising to keep at least one day clear from the riskier grey and black days, guiding safer outdoor planning. Note: This graph suggests potential risk, not guaranteed rainfall; expect most rain, if any, on days marked in grey and black.

Rancho Cucamonga, Sep 2025: Daily High Temperature Forecast Rancho Cucamonga High Temperature Trends for September 2025 86 34 85 33 84 32 83 31 82 30 81 29 80 28 79 27 78 26 Rancho Cucamonga, Sep 1: High Temp of 89°F /nRancho Cucamonga, Sep 1: High Temp of ?°C /n1 M Rancho Cucamonga, Sep 2: High Temp of 90°F /nRancho Cucamonga, Sep 2: High Temp of ?°C /n2 T Rancho Cucamonga, Sep 3: High Temp of 89°F /nRancho Cucamonga, Sep 3: High Temp of ?°C /n3 W Rancho Cucamonga, Sep 4: High Temp of 88°F /nRancho Cucamonga, Sep 4: High Temp of ?°C /n4 Th Rancho Cucamonga, Sep 5: High Temp of 88°F /nRancho Cucamonga, Sep 5: High Temp of ?°C /n5 F Rancho Cucamonga, Sep 6: High Temp of 88°F /nRancho Cucamonga, Sep 6: High Temp of ?°C /n6 S Rancho Cucamonga, Sep 7: High Temp of 89°F /nRancho Cucamonga, Sep 7: High Temp of ?°C /n7 Sn Rancho Cucamonga, Sep 8: High Temp of 88°F /nRancho Cucamonga, Sep 8: High Temp of ?°C /n8 M Rancho Cucamonga, Sep 9: High Temp of 88°F /nRancho Cucamonga, Sep 9: High Temp of ?°C /n9 T Rancho Cucamonga, Sep 10: High Temp of 88°F /nRancho Cucamonga, Sep 10: High Temp of ?°C /n10 W Rancho Cucamonga, Sep 11: High Temp of 86°F /nRancho Cucamonga, Sep 11: High Temp of ?°C /n11 Th Rancho Cucamonga, Sep 12: High Temp of 86°F /nRancho Cucamonga, Sep 12: High Temp of ?°C /n12 F Rancho Cucamonga, Sep 13: High Temp of 86°F /nRancho Cucamonga, Sep 13: High Temp of ?°C /n13 S Rancho Cucamonga, Sep 14: High Temp of 84°F /nRancho Cucamonga, Sep 14: High Temp of ?°C /n14 Sn Rancho Cucamonga, Sep 15: High Temp of 83°F /nRancho Cucamonga, Sep 15: High Temp of ?°C /n15 M Rancho Cucamonga, Sep 16: High Temp of 84°F /nRancho Cucamonga, Sep 16: High Temp of ?°C /n16 T Rancho Cucamonga, Sep 17: High Temp of 84°F /nRancho Cucamonga, Sep 17: High Temp of ?°C /n17 W Rancho Cucamonga, Sep 18: High Temp of 85°F /nRancho Cucamonga, Sep 18: High Temp of ?°C /n18 Th Rancho Cucamonga, Sep 19: High Temp of 85°F /nRancho Cucamonga, Sep 19: High Temp of ?°C /n19 F Rancho Cucamonga, Sep 20: High Temp of 85°F /nRancho Cucamonga, Sep 20: High Temp of ?°C /n20 S Rancho Cucamonga, Sep 21: High Temp of 86°F /nRancho Cucamonga, Sep 21: High Temp of ?°C /n21 Sn Rancho Cucamonga, Sep 22: High Temp of 85°F /nRancho Cucamonga, Sep 22: High Temp of ?°C /n22 M Rancho Cucamonga, Sep 23: High Temp of 82°F /nRancho Cucamonga, Sep 23: High Temp of ?°C /n23 T Rancho Cucamonga, Sep 24: High Temp of 81°F /nRancho Cucamonga, Sep 24: High Temp of ?°C /n24 W Rancho Cucamonga, Sep 25: High Temp of 81°F /nRancho Cucamonga, Sep 25: High Temp of ?°C /n25 Th Rancho Cucamonga, Sep 26: High Temp of 82°F /nRancho Cucamonga, Sep 26: High Temp of ?°C /n26 F Rancho Cucamonga, Sep 27: High Temp of 82°F /nRancho Cucamonga, Sep 27: High Temp of ?°C /n27 S Rancho Cucamonga, Sep 28: High Temp of 83°F /nRancho Cucamonga, Sep 28: High Temp of ?°C /n28 Sn Rancho Cucamonga, Sep 29: High Temp of 83°F /nRancho Cucamonga, Sep 29: High Temp of ?°C /n29 M Rancho Cucamonga, Sep 30: High Temp of 83°F /nRancho Cucamonga, Sep 30: High Temp of ?°C /n30 T

High Temperature Graph: Tracks daily forecasted highs. Vertical bars on each day highlight forecast variability, emphasizing trend analysis over precise predictions.

Rancho Cucamonga, Sep 2025: Daily Average Temperature Forecast Rancho Cucamonga Average Temperature Trends for September 2025 71 17 70 17 69 17 68 17 67 17 66 17 65 17 64 17 63 17 Rancho Cucamonga, Sep 1: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 1: Forecasted Average Temp of 22°C /n1 M Rancho Cucamonga, Sep 2: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 2: Forecasted Average Temp of 22°C /n2 T Rancho Cucamonga, Sep 3: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 3: Forecasted Average Temp of 22°C /n3 W Rancho Cucamonga, Sep 4: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 4: Forecasted Average Temp of 22°C /n4 Th Rancho Cucamonga, Sep 5: Forecasted Average Temp of 71°F /nRancho Cucamonga, Sep 5: Forecasted Average Temp of 22°C /n5 F Rancho Cucamonga, Sep 6: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 6: Forecasted Average Temp of 22°C /n6 S Rancho Cucamonga, Sep 7: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 7: Forecasted Average Temp of 22°C /n7 Sn Rancho Cucamonga, Sep 8: Forecasted Average Temp of 72°F /nRancho Cucamonga, Sep 8: Forecasted Average Temp of 22°C /n8 M Rancho Cucamonga, Sep 9: Forecasted Average Temp of 71°F /nRancho Cucamonga, Sep 9: Forecasted Average Temp of 22°C /n9 T Rancho Cucamonga, Sep 10: Forecasted Average Temp of 71°F /nRancho Cucamonga, Sep 10: Forecasted Average Temp of 22°C /n10 W Rancho Cucamonga, Sep 11: Forecasted Average Temp of 70°F /nRancho Cucamonga, Sep 11: Forecasted Average Temp of 21°C /n11 Th Rancho Cucamonga, Sep 12: Forecasted Average Temp of 70°F /nRancho Cucamonga, Sep 12: Forecasted Average Temp of 21°C /n12 F Rancho Cucamonga, Sep 13: Forecasted Average Temp of 70°F /nRancho Cucamonga, Sep 13: Forecasted Average Temp of 21°C /n13 S Rancho Cucamonga, Sep 14: Forecasted Average Temp of 69°F /nRancho Cucamonga, Sep 14: Forecasted Average Temp of 21°C /n14 Sn Rancho Cucamonga, Sep 15: Forecasted Average Temp of 69°F /nRancho Cucamonga, Sep 15: Forecasted Average Temp of 20°C /n15 M Rancho Cucamonga, Sep 16: Forecasted Average Temp of 69°F /nRancho Cucamonga, Sep 16: Forecasted Average Temp of 20°C /n16 T Rancho Cucamonga, Sep 17: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 17: Forecasted Average Temp of 20°C /n17 W Rancho Cucamonga, Sep 18: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 18: Forecasted Average Temp of 20°C /n18 Th Rancho Cucamonga, Sep 19: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 19: Forecasted Average Temp of 20°C /n19 F Rancho Cucamonga, Sep 20: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 20: Forecasted Average Temp of 20°C /n20 S Rancho Cucamonga, Sep 21: Forecasted Average Temp of 69°F /nRancho Cucamonga, Sep 21: Forecasted Average Temp of 21°C /n21 Sn Rancho Cucamonga, Sep 22: Forecasted Average Temp of 69°F /nRancho Cucamonga, Sep 22: Forecasted Average Temp of 20°C /n22 M Rancho Cucamonga, Sep 23: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 23: Forecasted Average Temp of 20°C /n23 T Rancho Cucamonga, Sep 24: Forecasted Average Temp of 66°F /nRancho Cucamonga, Sep 24: Forecasted Average Temp of 19°C /n24 W Rancho Cucamonga, Sep 25: Forecasted Average Temp of 67°F /nRancho Cucamonga, Sep 25: Forecasted Average Temp of 19°C /n25 Th Rancho Cucamonga, Sep 26: Forecasted Average Temp of 67°F /nRancho Cucamonga, Sep 26: Forecasted Average Temp of 19°C /n26 F Rancho Cucamonga, Sep 27: Forecasted Average Temp of 67°F /nRancho Cucamonga, Sep 27: Forecasted Average Temp of 20°C /n27 S Rancho Cucamonga, Sep 28: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 28: Forecasted Average Temp of 20°C /n28 Sn Rancho Cucamonga, Sep 29: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 29: Forecasted Average Temp of 20°C /n29 M Rancho Cucamonga, Sep 30: Forecasted Average Temp of 68°F /nRancho Cucamonga, Sep 30: Forecasted Average Temp of 20°C /n30 T

Average Temperature Graph: Illustrates daily average temperatures. Each point's vertical bar underscores the forecast's potential fluctuation, encouraging trend recognition throughout the month.

Rancho Cucamonga, Sep 2025: Daily Low Temperature Forecast Rancho Cucamonga Low Temperature Trends for September 2025 57 9 56 9 55 9 54 9 53 9 52 9 51 9 50 9 49 9 Rancho Cucamonga, September 1: Low Temp of 55°F /nRancho Cucamonga, September 1: Low Temp of 13°C /n1 M Rancho Cucamonga, September 2: Low Temp of 55°F /nRancho Cucamonga, September 2: Low Temp of 13°C /n2 T Rancho Cucamonga, September 3: Low Temp of 56°F /nRancho Cucamonga, September 3: Low Temp of 13°C /n3 W Rancho Cucamonga, September 4: Low Temp of 57°F /nRancho Cucamonga, September 4: Low Temp of 14°C /n4 Th Rancho Cucamonga, September 5: Low Temp of 55°F /nRancho Cucamonga, September 5: Low Temp of 13°C /n5 F Rancho Cucamonga, September 6: Low Temp of 56°F /nRancho Cucamonga, September 6: Low Temp of 13°C /n6 S Rancho Cucamonga, September 7: Low Temp of 56°F /nRancho Cucamonga, September 7: Low Temp of 13°C /n7 Sn Rancho Cucamonga, September 8: Low Temp of 56°F /nRancho Cucamonga, September 8: Low Temp of 13°C /n8 M Rancho Cucamonga, September 9: Low Temp of 55°F /nRancho Cucamonga, September 9: Low Temp of 13°C /n9 T Rancho Cucamonga, September 10: Low Temp of 55°F /nRancho Cucamonga, September 10: Low Temp of 13°C /n10 W Rancho Cucamonga, September 11: Low Temp of 55°F /nRancho Cucamonga, September 11: Low Temp of 13°C /n11 Th Rancho Cucamonga, September 12: Low Temp of 55°F /nRancho Cucamonga, September 12: Low Temp of 13°C /n12 F Rancho Cucamonga, September 13: Low Temp of 54°F /nRancho Cucamonga, September 13: Low Temp of 12°C /n13 S Rancho Cucamonga, September 14: Low Temp of 55°F /nRancho Cucamonga, September 14: Low Temp of 13°C /n14 Sn Rancho Cucamonga, September 15: Low Temp of 56°F /nRancho Cucamonga, September 15: Low Temp of 13°C /n15 M Rancho Cucamonga, September 16: Low Temp of 54°F /nRancho Cucamonga, September 16: Low Temp of 12°C /n16 T Rancho Cucamonga, September 17: Low Temp of 53°F /nRancho Cucamonga, September 17: Low Temp of 12°C /n17 W Rancho Cucamonga, September 18: Low Temp of 52°F /nRancho Cucamonga, September 18: Low Temp of 11°C /n18 Th Rancho Cucamonga, September 19: Low Temp of 52°F /nRancho Cucamonga, September 19: Low Temp of 11°C /n19 F Rancho Cucamonga, September 20: Low Temp of 52°F /nRancho Cucamonga, September 20: Low Temp of 11°C /n20 S Rancho Cucamonga, September 21: Low Temp of 53°F /nRancho Cucamonga, September 21: Low Temp of 12°C /n21 Sn Rancho Cucamonga, September 22: Low Temp of 53°F /nRancho Cucamonga, September 22: Low Temp of 12°C /n22 M Rancho Cucamonga, September 23: Low Temp of 54°F /nRancho Cucamonga, September 23: Low Temp of 12°C /n23 T Rancho Cucamonga, September 24: Low Temp of 52°F /nRancho Cucamonga, September 24: Low Temp of 11°C /n24 W Rancho Cucamonga, September 25: Low Temp of 53°F /nRancho Cucamonga, September 25: Low Temp of 12°C /n25 Th Rancho Cucamonga, September 26: Low Temp of 52°F /nRancho Cucamonga, September 26: Low Temp of 11°C /n26 F Rancho Cucamonga, September 27: Low Temp of 53°F /nRancho Cucamonga, September 27: Low Temp of 12°C /n27 S Rancho Cucamonga, September 28: Low Temp of 54°F /nRancho Cucamonga, September 28: Low Temp of 12°C /n28 Sn Rancho Cucamonga, September 29: Low Temp of 54°F /nRancho Cucamonga, September 29: Low Temp of 12°C /n29 M Rancho Cucamonga, September 30: Low Temp of 53°F /nRancho Cucamonga, September 30: Low Temp of 12°C /n30 T

Low Temperature Graph: Displays daily forecasted lows. Vertical rectangles on each plot point indicate forecast uncertainty, aiding in identifying temperature trends rather than exact figures.

September 2025 Summary

Precipitation Forecast
Average Precipitation
Rain Frequency 0 - 2 days
Temperature Forecast
Temperature Forecast Cooler Than Normal
Avg High Temps
Avg Low Temps