Year 2019 - Posted December 31, 2019: The decade is done, the average annual rain for the 2010's (2010 through 2019) came in at 9.63" at the San Diego Airport, thanks to a very wet 20. I continue to maintain the long term pattern of rain locally here in San Diego is not undergoing a major change. The 1975 level was the bottom of a long downtrend from 11.25" in 1944. I worked out a 30 year moving average analysis and while currently at 9.61" we are a downtrend from a peak of 11.10" in 2005, but we are still well above the previous chart valley of just 8.38" in 1975. Year 2021 - Posted January 1, 2022: The year came in at 7.85" almost exactly the same as last year's 7.83". There are just three years completed in the decade so far, so while the drop-off looks ominous, there have been six other 3-year spans which have come in that low going back to 1852 and an impressive 6 year span with each year below 8" starting in 1959 and ending in 1964. So perhaps the 2022-2023 season will be better! I've now started updating the decade chart (see below) for the 2020-2029 decade. However, on the first day of 2023 over an inch fell at the airport and January looks to be a rainy month. Year 2022 - Posted January 1, 2023: The year came in at 5.90" well below normal and the driest year in 9 years. Warmer temperatures cause more precipitation to fall as rain instead of snow over the mountains, and with a reduced snow pack there are reduced snow melts available to feed some reservoirs during the dry season. This means that the rate evaporation is increasing, which in turn increases the demand for irrigation (note: more research here is needed) My San Diego Temperature page shows a clear increase in temperature over the long term. However: Even if rainfall remains fairly constant on a per decade basis, there are three factors which are contributing to increased water shortages: According to the chart (see below) I prepared from the data file, grouping average rainfall by decade, rainfall has been remarkably steady. The long term pattern suggests there is not.
Is there major climate change going on here in San Diego as far as rain is concerned? This chart updated annually in early July San Diego Rainfall by Season in inches (July 1 through June 30) If you are looking for official NWS statistics for recent days and months, go to NWS San Diego Forecast Office (climate data). The current official NWS records go back to 1875 perhaps for this reason. I recall it being in something like nine different locations since 1850. Also the rain gage wasn't always at the same exact location, there's a story about this somewhere on the web. Some of the totals in the early years may result from incomplete data. The data was derived from NWS records going back to 1850, the link I use to have here no longer works. Scroll down for notes about recent rain activity and file updating. I try to keep the file "reasonably current". Then open a spreadsheet program and import the data from the saved text file. It is easy to bring the data into a spreadsheet. The data will come up as a separate page. Year, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec, YearTotal, NextJan, NextFeb, NextMar, NextApr, NextMay, NextJun, SeasonTotalĭOWNLOAD: File is here (sandiegorain.txt). The file is comma delimited, in the format of: I have developed a file of monthly San Diego rainfall data which presents the data by both calendar year AND by season (running from July to June).įor commentary on recent rain events or ongoing rain activity see Weather Notes. Most records are kept by calendar year, but San Diego's weather is highly seasonal with most of the rain falling in the November-March time period.
As a San Diego resident I've found it hard to find a convenient place to find annual rainfall data for San Diego in a useful format.
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