Fontana (CA) Temperature by Month
The average annual maximum temperature in Fontana, California, United States of America is 26°C (79°F), with daytime highs ranging from 18°C (64°F) in December to 35°C (95°F) in August. This page covers monthly averages, day-night differences, and how Fontana compares to cities worldwide.
Fontana Monthly Temperatures
Visitors to Fontana will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 18°C (64°F) in August to 7°C (45°F) in December.
The chart below illustrates the average maximum day and minimum night temperatures in Fontana by month:
Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM. August, the warmest month, sees 351 hours of sunshine.
The chart below shows the average temperature throughout the year:
Temperature: Fontana vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Fontana vs World: Temperature Compared
Fontana's average annual maximum temperature is 26°C (79°F). To put that in context, here's how it compares to a few well-known destinations:
Lisbon, Portugal averages 21°C (70°F) annually — warm summers, mild winters, and rain mainly in the cooler months.
On the cooler end, Oslo, Norway averages just 10°C (50°F) annually, with pleasant summers but long, cold winters.
Shanghai, China averages 21°C (70°F) a year, with warm summers, mild winters, and a noticeable spring and autumn.
Adelaide, Australia averages 21°C (70°F) a year, with warm summers, mild winters, and relatively low rainfall year-round.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Global average temperatures have risen by around 1.2°C since the pre-industrial era, and the effects are visible across many regions. Winters are milder on average, with fewer frost days and less snow in many parts of the world. Heatwaves are more frequent and more intense, and Europe's summers of 2018, 2019, and 2020 all set records.
Summers are also getting drier in some areas, while winter rainfall has increased in others. This contributies to higher river levels and more flooding. In many countries, spring arrives earlier and autumn lasts longer. It has knock-on effects for wildlife, agriculture, and local ecosystems.
For more on Fontana's weather — including monthly rainfall, sunshine hours, and humidity — visit our Fontana climate page.
