San Francisco: August Days over 90 Degrees
This figure is based on historical data (for the 1980's & 1990's) and best-guess climate change projections (for the 2050's) under a scenario of greenhouse gas emissions lower than the current trend—thus a conservative scenario. Climate Central used established methods to apply regional results averaged from twelve major global climate models to the cities listed here. The values are projections of long-term averages, not predictions for any given year; actual outcomes will vary significantly from year to year due to natural variability. Furthermore, because the modeling and methods used involve uncertainty, values should be taken as best guesses within a range of uncertainty. True long-term averages will likely prove somewhat higher or lower than the projections here. However, all twelve models are unanimous in projecting increased hot days from the present by the middle of the century.
The comparison city has a historical average August dew point within ten degrees of the first city, making them reasonably similar in terms of the feel of humidity.
For additional information, please see the August Heat feature.