July is one of the warmer months of the year in San Mateo, with average highs near 17.4°C and lows around 12.7°C (mean 15.1°C). It is one of the drier months, averaging 2 mm of rainfall and 86% relative humidity across the period.
July is one of the warmer months of the year in San Mateo. Across 45 years of records, the warmest July in San Mateo was 2015 — when the month averaged 17.2°C — while the coldest was 2010 at 13.8°C. Typical July days reach 17.4°C with nights near 12.7°C. The long-term July temperature trend is broadly flat.
July is one of the drier months in San Mateo, averaging 2 mm of rainfall. The wettest July on record was 2000 with 12 mm, while the driest was 2023 at 0 mm.
Relative humidity in San Mateo during July averages 86%. The most humid July was 2005 at 90%, and the least humid was 1984 at 80%.
July receives about 6.5 kWh/m²/day of solar energy in San Mateo. The sunniest July was 1989 at 7.3 kWh/m²/day, and the cloudiest was 1994 at 5.6.
Average wind speed in San Mateo during July is 3.4 m/s. The windiest July was 1989 at 4.6 m/s, while the calmest was 2005 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.2°C | 15.1°C | 14.8°C | 15.2°C | 14.8°C | -0.4°C |
| Avg High | 17.9°C | 17.6°C | 17.0°C | 17.3°C | 16.9°C | -1°C |
| Avg Low | 12.5°C | 12.6°C | 12.6°C | 13.0°C | 12.7°C | +0.2°C |
| Avg Rain | 1 mm | 2 mm | 3 mm | 2 mm | 1 mm | 0 mm |
July temperatures in San Mateo have fallen by about 0.5°C between 1981–1985 and 2021–2025.
July has ranged from a record low of 9.8°C (1999) to a record high of 27.6°C (1993).
Rainfall in July is one of the drier months, averaging 2 mm, with a wettest year of 12 mm.
Daytime highs and overnight lows have shifted differently — highs fell about 0.2°C per decade while lows rose 0.1°C per decade, narrowing the gap between day and night.
One of the best times to visit San Mateo
July is one of the best times to visit San Mateo. Expect days averaging 17.4°C and nights around 12.7°C (mean 15.1°C) — warmer than San Mateo's yearly average — with low rainfall (2 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 16.1°C | 14.2°C | 12.3°C | 17.6°C | 11.1°C | 2 mm | 87% | 3.5 m/s | 6.6 |
| 2024 | 18.2°C | 15.8°C | 13.5°C | 22.0°C | 12.1°C | 1 mm | 84% | 3.2 m/s | 6.9 |
| 2023 | 16.9°C | 14.7°C | 12.5°C | 19.1°C | 11.6°C | 0 mm | 88% | 3.7 m/s | 6.9 |
| 2022 | 17.0°C | 15.0°C | 13.0°C | 18.9°C | 11.9°C | 3 mm | 86% | 3.8 m/s | 6.6 |
| 2021 | 16.5°C | 14.3°C | 12.1°C | 21.7°C | 10.9°C | 1 mm | 85% | 3.2 m/s | 6.3 |
| 2020 | 16.9°C | 14.7°C | 12.5°C | 19.1°C | 11.9°C | 0 mm | 86% | 3.7 m/s | 6.8 |
| 2019 | 17.3°C | 15.2°C | 13.2°C | 19.4°C | 12.2°C | 0 mm | 88% | 4.1 m/s | 6.9 |
| 2018 | 17.8°C | 15.6°C | 13.5°C | 19.5°C | 12.3°C | 1 mm | 85% | 3.5 m/s | 6.5 |
| 2017 | 17.2°C | 14.8°C | 12.4°C | 19.8°C | 11.4°C | 0 mm | 86% | 3.5 m/s | 7 |
| 2016 | 16.9°C | 14.8°C | 12.6°C | 20.3°C | 11.4°C | 1 mm | 87% | 3.5 m/s | 6.9 |
| 2015 🔥 | 19.4°C | 17.2°C | 15.1°C | 24.6°C | 13.9°C | 4 mm | 84% | 3.3 m/s | 6.3 |
| 2014 | 18.9°C | 16.6°C | 14.2°C | 23.7°C | 11.7°C | 1 mm | 84% | 2.9 m/s | 6.2 |
| 2013 | 17.1°C | 15.0°C | 13.0°C | 19.9°C | 11.8°C | 2 mm | 85% | 3.2 m/s | 6 |
| 2012 | 16.1°C | 14.2°C | 12.2°C | 18.5°C | 11.2°C | 5 mm | 86% | 3.6 m/s | 6.5 |
| 2011 | 16.5°C | 14.3°C | 12.2°C | 20.2°C | 11.1°C | 1 mm | 88% | 3.3 m/s | 6.4 |
| 2010 ❄️ | 15.7°C | 13.8°C | 11.8°C | 17.8°C | 10.5°C | 1 mm | 87% | 3.2 m/s | 6.3 |
| 2009 | 16.8°C | 14.5°C | 12.3°C | 24.5°C | 11.3°C | 4 mm | 87% | 3.4 m/s | 6.5 |
| 2008 | 17.2°C | 14.9°C | 12.6°C | 25.4°C | 11.1°C | 2 mm | 86% | 3.5 m/s | 6.5 |
| 2007 | 17.4°C | 15.4°C | 13.3°C | 19.3°C | 11.3°C | 2 mm | 87% | 3.3 m/s | 6.7 |
| 2006 | 17.7°C | 15.3°C | 13.0°C | 22.6°C | 10.7°C | 1 mm | 88% | 3.1 m/s | 7.1 |
| 2005 | 17.1°C | 14.8°C | 12.6°C | 21.5°C | 11.5°C | 5 mm | 90% | 2.8 m/s | 6.7 |
| 2004 | 17.5°C | 15.4°C | 13.2°C | 20.1°C | 12.1°C | 0 mm | 87% | 3.1 m/s | 6.1 |
| 2003 | 16.9°C | 14.5°C | 12.2°C | 18.8°C | 11.1°C | 2 mm | 88% | 3.4 m/s | 6.7 |
| 2002 | 16.9°C | 14.7°C | 12.4°C | 20.2°C | 11.3°C | 0 mm | 86% | 3.2 m/s | 6.6 |
| 2001 | 16.6°C | 14.6°C | 12.6°C | 19.4°C | 11.3°C | 1 mm | 86% | 3.5 m/s | 6.2 |
| 2000 🌧️ | 16.0°C | 14.1°C | 12.2°C | 17.8°C | 11.1°C | 12 mm | 88% | 3.9 m/s | 6.4 |
| 1999 | 16.2°C | 13.9°C | 11.7°C | 20.2°C | 9.8°C | 6 mm | 84% | 3.8 m/s | 6.6 |
| 1998 | 17.2°C | 14.9°C | 12.6°C | 22.2°C | 11.0°C | 1 mm | 88% | 3.3 m/s | 6.4 |
| 1997 | 18.0°C | 15.5°C | 13.1°C | 21.9°C | 12.2°C | 1 mm | 86% | 3.5 m/s | 6.5 |
| 1996 | 17.4°C | 14.9°C | 12.3°C | 22.2°C | 11.2°C | 1 mm | 86% | 2.9 m/s | 6.4 |
| 1995 | 18.7°C | 16.1°C | 13.5°C | 27.3°C | 12.3°C | 1 mm | 86% | 3.2 m/s | 7 |
| 1994 | 16.4°C | 14.1°C | 11.7°C | 18.8°C | 9.9°C | 3 mm | 86% | 2.9 m/s | 5.6 |
| 1993 | 18.0°C | 15.0°C | 12.1°C | 27.6°C | 10.9°C | 1 mm | 84% | 3.5 m/s | 6.7 |
| 1992 | 18.9°C | 16.4°C | 13.9°C | 22.8°C | 11.8°C | 1 mm | 84% | 3.4 m/s | 6.3 |
| 1991 | 17.2°C | 14.7°C | 12.2°C | 24.3°C | 11.0°C | 3 mm | 86% | 2.9 m/s | 6.2 |
| 1990 | 18.1°C | 15.6°C | 13.1°C | 22.5°C | 11.6°C | 2 mm | 86% | 3 m/s | 6.3 |
| 1989 | 17.3°C | 14.6°C | 11.9°C | 18.8°C | 10.9°C | 1 mm | 85% | 4.6 m/s | 7.3 |
| 1988 | 18.4°C | 15.5°C | 12.6°C | 24.9°C | 10.8°C | 1 mm | 83% | 3.3 m/s | 6.5 |
| 1987 | 17.5°C | 14.9°C | 12.4°C | 23.2°C | 11.3°C | 1 mm | 83% | 4.2 m/s | 7.1 |
| 1986 | 17.7°C | 15.1°C | 12.4°C | 20.5°C | 11.1°C | 1 mm | 84% | 3.4 m/s | 6.4 |
| 1985 | 18.2°C | 15.5°C | 12.8°C | 23.5°C | 11.0°C | 2 mm | 82% | 3.3 m/s | 6.2 |
| 1984 | 18.9°C | 16.1°C | 13.3°C | 23.4°C | 11.4°C | 2 mm | 80% | 3.2 m/s | 6.4 |
| 1983 | 18.1°C | 15.5°C | 12.9°C | 23.7°C | 11.5°C | 2 mm | 85% | 4.3 m/s | — |
| 1982 | 17.1°C | 14.6°C | 12.0°C | 20.1°C | 11.1°C | 2 mm | 86% | 4 m/s | — |
| 1981 | 17.9°C | 14.9°C | 11.9°C | 23.1°C | 11.2°C | 1 mm | 83% | 3.4 m/s | — |
Actual recorded July data for each year, 1981–2025 — sourced from NASA POWER.
The average high in July is around 17.4°C with lows near 12.7°C (mean 15.1°C), based on 45 years of NASA POWER data.
July averages 2 mm of rainfall in San Mateo, one of the drier months. The wettest on record was 12 mm in 2000.
The hottest July reached 27.6°C in 1993. The coldest dipped to 9.8°C in 1999.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average July temperatures have fallen by about 0.5°C — but days and nights have moved in opposite directions. Overnight lows rose from 12.6°C to 12.7°C while daytime highs eased from 18°C to 16.9°C, narrowing the gap between day and night.
July is one of the warmer months of the year in San Mateo and one of the drier months, so plan for around 17.4°C daytime highs and 12.7°C at night.
Not quite — July is the 9th coolest month in San Mateo, averaging 15.1°C.
For July in San Mateo, pack light layers you can adjust through the day, with typical highs of 17.4°C and lows of 12.7°C.
Relative humidity in July averages 86% — quite humid.
Average wind speed in July is 3.4 m/s. The windiest July on record averaged 4.6 m/s (1989).
The wettest July on record was 2000 with 12 mm. On average, July sees 2 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 San Mateo behaves each July, 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 July specifically, along with year-by-year records and how the month has changed over the decades.
