Past, Present, and Future

 100 Million Years Ago

100 million years ago Los Angeles was a much different place.  It was underwater!  The water was much warmer than it is today.  Today the water temperature off the coast is around 60 degrees Fahrenheit; 100 million years ago the water temperature was much warmer somewhere around 80 degrees Fahrenheit.  Los Angeles is underwater so it would have had a steady temperature pretty much year-round.  Since the climate was much more tropical it can be assumed that the average amount of precipitation was much greater than it is currently.  Right now LA averages less than 20 inches of rainfall each year; 100 million years ago this number was probably three times that amount or 60 inches plus a year.

 

Current Average Temperatures (weather.com)

Current Average Precipitation

Past Average Temperatures

In the future it looks as though Los Angeles will once again be underwater.  Not only will it be under water but it will have moved closer to the equator.  So the water temperature will be even warmer.  My guess would be about 85 degrees Fahrenheit.  The earth will be in a warming period so it stands to reason that the water temperature will be much warmer and being located closer to the equator will only amplify this.  The average annual precipitation will be much greater than it is today probably 60 or more inches each year.  This is due to the tropical nature of the climate and the new location (closer to the equator).

The Future?

Future Average Temperatures

Comparison of the Climate in LA to the Climate in Milan, Italy

I based this comparison on the Milan, Italy weather blog by Alina Yurievna Shemetova.

Koppen-Geiger Classification

Los Angeles is classified as a dry-summer subtropical climate. This means that the area has rainy winters and mild dry summers. This is due to the relatively cold ocean currents that are present off the California coast.  Milan is classified as a oceanic climate.  This means that the area has cool summers but relatively mild winters.

                                    (Source: http://koeppen-geiger.vu-wien.ac.at/)

 

Meso-scale

The climate in Milan is affected by its proximity to a large body of water, the Mediterranean (specifically the Adriatic and Ligurian seas).  This plays a major role in the amount of precipitation that Milan receives as well as helps to moderate the temperature.  In addition, the Alps are located just to the north which can also influence the precipitation and climate.  LA is similarly situated with the Pacific Ocean to the west and the San Gabriel Mountains to the east.

Micro-scale

The urban heat island effect is quite strong in Milan.  There is a marked difference in temperatures between 1997 and 2011 according to the data in Alina's blog.  LA has a similar heat island in the Valley.  In addition LA experiences the seasonal Santa Ana winds.

LA Climatology

Koppen-Geiger Classification

Under this classification Los Angeles would be classified as a dry-summer subtropical climate. This means that the area has rainy winters and mild dry summers. This is due to the relatively cold ocean currents that are present off the California coast.

                                    (Source: http://koeppen-geiger.vu-wien.ac.at/)

Climate Controls

Meso-scale influences for Los Angeles include its close proximity to the Pacific Ocean (west) and the San Gabriel Mountains (east).

Micro-scale influences include the Valley where the central portion of the city is located, as well as the seasonal Santa Ana winds. In addition, the urban heat island effect can be quite strong in the Valley.