Weather

Point Blue Conservation Science established a weather station at TomKat Ranch in September 2010. Since then, we have observed consistently warm weather, new record temperatures, and extreme drought conditions.

Updated: March 7, 2025

Daily weather

Daily high temperature, low temperature, and precipitation from the TomKat weather station, along with the normal monthly range of temperatures observed since the weather station was established. Note: Gaps in weather data occurred when the weather station was being upgraded.

In 2022, TomKat experienced a new record high temperature of 99.2°F on September 06, 2022, beating the previous record of 97°F set on September 06, 2020. 2024 was slightly cooler, with the lowest temperature of 26.4°F recorded on September 23. The single rainiest day in 2024 was 3.22 inches on November 22. The rainiest day ever recorded was December 11, 2014, with a total of 7.74 inches.

Click & drag the slider at the bottom to view different dates.

Consistently warm weather

TomKat’s high temperatures have been warmer than estimated historic averages in almost every month since November 2017, including during the growing season (March-June, shaded). Low temperatures were warmer than historic averages particularly during the extended drought.

Values greater than zero are above the estimated historic average (1980-2010)*, and values below zero are below average.

*Historic averages are estimated from comparing current TomKat and Half Moon Bay data, and applying corrections to historical averages from Half Moon Bay, 1981-2010.

Recovery from extended drought

We examined two drought indices from the National Centers for Environmental Information: the Palmer Drought Severity Index (PDSI) and the Palmer Z Index. The PDSI is an indicator of long-term drought that takes into account precipitation and temperature over several months, while the Z index measures short-term drought on a monthly scale, and can better reflect recent storms and soil moisture conditions.

Palmer Drought Severity Index (PDSI)

The PDSI for Central Coastal California entered drought conditions early in 2013, which persisted nearly 4 years until October 2016, including over two years of extreme drought from June 2013 through November 2015. Conditions were largely normal through 2017, returned to moderate drought for much of 2018, and progressed to extreme drought again through the end of 2022. Average rainfall in 2023 and 2024 improved drought conditions.

In the legend at top right, click on the lines for North Coast and South Coast to compare how these regions have fared over the same time period. During the extended drought, conditions in Northern Coastal California were never quite as dry, and Southern Coastal California generally fared worse. Northern and Southern Coastal California were also in the normal range throughout much of 2019, and in 2020 have switched places such that Northern Coastal California is currently the driest.

Palmer Z Index (PZI)

The PZI more readily shows the impact of big storms, such as the extremely moist conditions recently in December 2022, January 2023, and March 2023.

In the legend at top right, click on the lines for North Coast and South Coast to compare how these regions have fared over the same time period.


About this page

This interactive web page was produced in R using rmarkdown and the plotly package. The code used to produce this web page is available on Github.

For more information

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