Climate averages 1991–2020
Union City weather
in July.
A warm, very dry month: the 2nd warmest and the driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
July is a warm month in Union City: daytime highs average 27.9°C and nights cool to about 14.8°C. By daytime temperature it is the 2nd warmest of the 12 months.
Rain is very rare: less than 1 mm falls in a typical July (the driest month of the year). Daylight, from sunrise to sunset, lasts about 14 h 29 min on an average July day.
The nearest other city in this atlas is Fremont (6 km away). In July its highs average 27.5°C, about as warm as Union City, with almost no rain (under 1 mm).
Among the 498 cities listed in the United States, Union City ranks joint 363rd of 498 for the warmest July highs and joint 35th of 498 for the driest July (rainfall, lowest first). The mean July high of those 498 cities is 30.3°C; Union City is 2.4°C cooler than that mean.
From July to August, average highs rise by 0.1°C to 28.0°C, and monthly rainfall rises from under 1 mm to 1.0 mm.
The annual picture
July in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Union City climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 14.3°C5.9°C | 5.9°C | 91 | 8.9 | 9.910 h |
| February | 15.5°C6.9°C | 6.9°C | 96 | 9.1 | 10.811 h |
| March | 17.2°C8.2°C | 8.2°C | 75 | 9.1 | 11.912 h |
| April | 19.1°C9.2°C | 9.2°C | 40 | 5.7 | 13.113 h |
| May | 22.1°C11.1°C | 11.1°C | 19 | 3.4 | 14.214 h |
| June | 25.6°C13.0°C | 13.0°C | 4.0 | 0.9 | 14.715 h |
| July, selected | 27.9°C14.8°C | 14.8°C | 0.9 | 0.2 | 14.514 h |
| August | 28.0°C15.1°C | 15.1°C | 1.0 | 0.2 | 13.614 h |
| September | 27.4°C15.1°C | 15.1°C | 1.9 | 0.4 | 12.512 h |
| October | 23.7°C13.1°C | 13.1°C | 23 | 2.9 | 11.311 h |
| November | 17.8°C9.3°C | 9.3°C | 43 | 5.7 | 10.210 h |
| December | 14.0°C6.3°C | 6.3°C | 83 | 8.9 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
July in nearby cities
- Fremont in JulyUnited States · 6 kmHigh 27.5°C · Low 14.8°C · 0.9 mm rain
- Hayward in JulyUnited States · 10 kmHigh 26.5°C · Low 14.1°C · 0.7 mm rain
- Pleasanton in JulyUnited States · 15 kmHigh 29.0°C · Low 14.7°C · 1.0 mm rain
- San Ramon in JulyUnited States · 21 kmHigh 28.1°C · Low 14.4°C · 0.7 mm rain
- Milpitas in JulyUnited States · 21 kmHigh 28.5°C · Low 15.3°C · 0.9 mm rain
- Redwood City in JulyUnited States · 23 kmHigh 24.2°C · Low 13.9°C · 0.5 mm rain
- Mountain View in JulyUnited States · 24 kmHigh 26.0°C · Low 14.4°C · 0.9 mm rain
- Livermore in JulyUnited States · 24 kmHigh 29.7°C · Low 14.7°C · 1.0 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Union City) is explained once on the Union City year overview and on the Sources, method and limits page.
Fremont, Mountain View and Milpitas lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.