October is one of the warmer months of the year in Sunnyvale, with average highs near 25.2°C and lows around 10.1°C (mean 17.7°C). It is one of the drier months, averaging 29 mm of rainfall and 64% relative humidity across the period.
October is one of the warmer months of the year in Sunnyvale. Across 45 years of records, the warmest October in Sunnyvale was 2020 — when the month averaged 20.9°C — while the coldest was 1984 at 15°C. Typical October days reach 25.2°C with nights near 10.1°C. The long-term trend is warming, about 0.3°C per decade.
October is one of the drier months in Sunnyvale, averaging 29 mm of rainfall. The wettest October on record was 2021 with 137 mm, while the driest were 2002, 2019 and 2020 at 0 mm.
Relative humidity in Sunnyvale during October averages 64%. The most humid October was 2025 at 75%, and the least humid was 2019 at 48%.
October receives about 3.9 kWh/m²/day of solar energy in Sunnyvale. The sunniest October was 2019 at 4.6 kWh/m²/day, and the cloudiest was 1988 at 2.9.
Average wind speed in Sunnyvale during October is 1.8 m/s. The windiest Octobers were 1996 and 2021 at 2.2 m/s, while the calmest was 1987 at 1.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.0°C | 17.9°C | 16.9°C | 18.2°C | 18.7°C | +1.7°C |
| Avg High | 24.5°C | 25.8°C | 24.2°C | 25.6°C | 26.3°C | +1.8°C |
| Avg Low | 9.5°C | 10.0°C | 9.7°C | 10.7°C | 11.2°C | +1.7°C |
| Avg Rain | 33 mm | 21 mm | 34 mm | 25 mm | 33 mm | 0 mm |
October temperatures in Sunnyvale have risen by about 2.1°C between 1981–1985 and 2021–2025.
October has ranged from a record low of 1.9°C (1996) to a record high of 41.5°C (2024).
Rainfall in October is one of the drier months, averaging 29 mm, with a wettest year of 137 mm.
A good time to visit Sunnyvale
October is a good time to visit Sunnyvale, with days averaging 25.2°C and nights around 10.1°C (mean 17.7°C, warmer than Sunnyvale's yearly average) and low rainfall. August and July are marginally more temperate, but October still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 23.7°C | 17.1°C | 10.5°C | 32.2°C | 7.1°C | 47 mm | 75% | 1.7 m/s | 3.7 |
| 2024 | 28.3°C | 20.4°C | 12.6°C | 41.5°C | 6.8°C | 3 mm | 57% | 1.8 m/s | 4.4 |
| 2023 | 26.9°C | 19.2°C | 11.4°C | 37.3°C | 3.3°C | 8 mm | 61% | 1.7 m/s | 4.1 |
| 2022 | 26.3°C | 18.1°C | 9.9°C | 33.9°C | 6.0°C | 1 mm | 66% | 1.7 m/s | 3.6 |
| 2021 🌧️ | 22.9°C | 16.7°C | 10.5°C | 35.6°C | 5.9°C | 137 mm | 66% | 2.2 m/s | 3.9 |
| 2020 🔥 | 29.7°C | 20.9°C | 12.1°C | 37.2°C | 6.4°C | 0 mm | 49% | 1.6 m/s | 4 |
| 2019 | 26.2°C | 17.7°C | 9.3°C | 33.6°C | 2.1°C | 0 mm | 48% | 1.8 m/s | 4.6 |
| 2018 | 26.3°C | 18.5°C | 10.6°C | 31.2°C | 8.1°C | 5 mm | 62% | 1.7 m/s | 4.1 |
| 2017 | 26.9°C | 18.6°C | 10.4°C | 33.2°C | 6.1°C | 6 mm | 51% | 1.8 m/s | 4.4 |
| 2016 | 23.0°C | 16.8°C | 10.6°C | 33.7°C | 7.5°C | 118 mm | 72% | 2.1 m/s | 3.6 |
| 2015 | 28.1°C | 20.4°C | 12.7°C | 37.1°C | 9.5°C | 4 mm | 66% | 1.6 m/s | 4.1 |
| 2014 | 27.4°C | 20.0°C | 12.6°C | 37.2°C | 8.4°C | 18 mm | 63% | 1.7 m/s | 4 |
| 2013 | 24.9°C | 16.9°C | 8.9°C | 31.7°C | 6.6°C | 1 mm | 55% | 1.7 m/s | 4.2 |
| 2012 | 24.7°C | 17.7°C | 10.6°C | 39.3°C | 5.8°C | 21 mm | 68% | 1.9 m/s | 3.9 |
| 2011 | 24.6°C | 17.6°C | 10.6°C | 32.5°C | 4.6°C | 36 mm | 70% | 1.6 m/s | 3.8 |
| 2010 | 24.0°C | 17.3°C | 10.6°C | 36.7°C | 3.5°C | 40 mm | 67% | 1.9 m/s | 3.5 |
| 2009 | 21.9°C | 15.6°C | 9.4°C | 29.8°C | 4.4°C | 107 mm | 72% | 2.1 m/s | 3.9 |
| 2008 | 26.0°C | 18.1°C | 10.2°C | 33.3°C | 4.1°C | 19 mm | 54% | 1.9 m/s | 4.1 |
| 2007 | 22.6°C | 15.8°C | 8.9°C | 32.4°C | 5.2°C | 36 mm | 71% | 1.8 m/s | 3.9 |
| 2006 | 24.1°C | 16.8°C | 9.5°C | 31.3°C | 6.3°C | 6 mm | 61% | 1.7 m/s | 3.7 |
| 2005 | 24.4°C | 17.0°C | 9.5°C | 32.9°C | 6.9°C | 7 mm | 68% | 1.9 m/s | 4 |
| 2004 | 22.9°C | 16.1°C | 9.2°C | 35.3°C | 4.6°C | 74 mm | 70% | 2 m/s | 3.7 |
| 2003 | 27.0°C | 18.8°C | 10.5°C | 34.3°C | 4.9°C | 3 mm | 60% | 1.9 m/s | 4.3 |
| 2002 | 24.6°C | 17.2°C | 9.7°C | 35.8°C | 5.5°C | 0 mm | 63% | 1.8 m/s | 3.8 |
| 2001 | 25.6°C | 18.1°C | 10.6°C | 35.5°C | 6.9°C | 10 mm | 64% | 1.8 m/s | 3.5 |
| 2000 | 22.4°C | 15.7°C | 9.0°C | 33.1°C | 5.8°C | 74 mm | 74% | 2 m/s | 3.6 |
| 1999 | 27.6°C | 19.0°C | 10.4°C | 35.1°C | 5.7°C | 11 mm | 59% | 1.6 m/s | 3.9 |
| 1998 | 23.5°C | 16.0°C | 8.4°C | 30.9°C | 4.4°C | 20 mm | 65% | 1.9 m/s | 4.2 |
| 1997 | 24.2°C | 16.8°C | 9.4°C | 33.5°C | 5.1°C | 17 mm | 66% | 2 m/s | 4.1 |
| 1996 | 23.9°C | 16.4°C | 8.9°C | 38.8°C | 1.9°C | 35 mm | 65% | 2.2 m/s | 3.9 |
| 1995 | 27.2°C | 18.7°C | 10.2°C | 34.0°C | 7.1°C | 2 mm | 57% | 1.8 m/s | 4.1 |
| 1994 | 24.7°C | 17.0°C | 9.3°C | 32.0°C | 3.5°C | 13 mm | 63% | 1.8 m/s | 4.2 |
| 1993 | 25.5°C | 18.2°C | 10.9°C | 30.8°C | 7.9°C | 13 mm | 62% | 1.6 m/s | 3.7 |
| 1992 | 26.3°C | 18.9°C | 11.6°C | 35.1°C | 8.4°C | 38 mm | 65% | 1.7 m/s | 3.8 |
| 1991 | 27.8°C | 19.5°C | 11.3°C | 36.4°C | 3.7°C | 52 mm | 55% | 1.9 m/s | 3.6 |
| 1990 | 26.8°C | 18.2°C | 9.6°C | 34.3°C | 5.0°C | 6 mm | 57% | 1.8 m/s | 4.3 |
| 1989 | 24.0°C | 16.6°C | 9.3°C | 32.0°C | 2.5°C | 45 mm | 67% | 1.8 m/s | 4 |
| 1988 | 26.6°C | 18.3°C | 10.0°C | 32.9°C | 7.0°C | 6 mm | 64% | 1.6 m/s | 2.9 |
| 1987 | 27.5°C | 19.7°C | 11.8°C | 38.6°C | 7.5°C | 25 mm | 60% | 1.4 m/s | 3.4 |
| 1986 | 24.9°C | 16.9°C | 9.0°C | 30.6°C | 5.9°C | 2 mm | 64% | 1.6 m/s | 3.5 |
| 1985 | 24.5°C | 16.4°C | 8.4°C | 36.9°C | 4.8°C | 26 mm | 62% | 1.8 m/s | 3.9 |
| 1984 ❄️ | 22.0°C | 15.0°C | 8.1°C | 29.7°C | 3.3°C | 58 mm | 72% | 2.1 m/s | 3.8 |
| 1983 | 25.2°C | 18.1°C | 11.0°C | 31.4°C | 7.9°C | 13 mm | 68% | 1.6 m/s | — |
| 1982 | 23.1°C | 16.3°C | 9.4°C | 28.3°C | 5.1°C | 62 mm | 66% | 1.7 m/s | — |
| 1981 | 22.3°C | 15.3°C | 8.2°C | 31.7°C | 4.6°C | 58 mm | 68% | 1.8 m/s | — |
Actual recorded October data for each year, 1981–2025 — sourced from NASA POWER.
The average high in October is around 25.2°C with lows near 10.1°C (mean 17.7°C), based on 45 years of NASA POWER data.
October averages 29 mm of rainfall in Sunnyvale, one of the drier months. The wettest on record was 137 mm in 2021.
The hottest October reached 41.5°C in 2024. The coldest dipped to 1.9°C in 1996.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average October temperatures have risen by about 2.1°C. Daytime highs moved from 23.4°C to 25.6°C and overnight lows from 9°C to 11°C over the same span.
October is one of the warmer months of the year in Sunnyvale and one of the drier months, so plan for around 25.2°C daytime highs and 10.1°C at night.
Not quite — October is the 8th coolest month in Sunnyvale, averaging 17.7°C.
For October in Sunnyvale, pack light layers you can adjust through the day, with typical highs of 25.2°C and lows of 10.1°C.
Relative humidity in October averages 64% — moderately humid.
Average wind speed in October is 1.8 m/s. The windiest October on record averaged 2.2 m/s (1996).
The wettest October on record was 2021 with 137 mm. On average, October sees 29 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Sunnyvale behaves each October, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for October specifically, along with year-by-year records and how the month has changed over the decades.
