Back in the early 2020s I began publishing data on temperature at the time of a rattlesnake removal, and released data for a couple of years. I decided to sit on a few years of data to publish a bunch in a single analysis to help paint a broader picture of how air temperature plays into rattlesnake encounters with people. In this analysis, we get to visualize 3 new years of data: 2023, 2024, and 2025. I also threw in 2022’s data (previously released) to have a preexisting baseline dataset to help speed up getting in the new data. I was going to remove 2022’s data in the final analysis, but decided to keep it, as I’m sure quite a few folks reading this now will not have seen that data before today.
Below is the visual graph of the percentage of snakes removed for each given year (2022 – 2025) in differing temperature brackets, the same way I’ve visualized data in the past. Except in this case, instead of a single year of data, we get to see 4 years of data side-by-side for comparison.
Data for the individual snake seasons of 2022, 2023, 2024, and 2025.
In the above visualization, you can see the temperature range for removals ranges over 50 degrees fahrenheit, with the minimum removal temperature being 44 °F (a rattlesnake inside a home on a cool night in Nevada county, in December, where it was overwintering). The maximum temperature at the time of a removal was 106 °F during a heatwave in early September, where a rattlesnake was hiding under a dense bush in as cool a spot it could find.
Without question, over the 4 years of data, it’s easy to see that the majority of rattlesnakes get removed between the temperatures of 70 °F and 90 °F, though some still get found and removed in temperatures above and below that range.
Here’s some of the more notable stats from the data:
- 78% of removals occur between 70 – 90 °F
- refining that temperature range further, 65% of removals occur between 75 – 89 °F
- 17% of removals occur above (>) 90 °F
- just under 5% of removals occur below (<) 70 °F
The most prolific single temperature bracket is the 80 – 84 °F range, where over 25% of removals occur.
Combined data for the years of 2022, 2023, 2024, and 2025. This helps fully visualize the busiest temperature brackets for removals.
What this data means
Generally, rattlesnake encounters with people and pets occur during temperatures that are also most comfortable for humans (and pets) to be outside. Snakes, like many other animals, enjoy the same air temperatures/conditions we tend to find fairly comfortable, which leads to the majority of encounters occurring in this favorable temperature range. Temperatures higher than around 90 – 95 °F can become dangerous for snakes, especially in areas with limited shade/shelter, just as it can be dangerous for people. Similarly, people don’t often encounter snakes in cooler temperatures, generally because most snakes are tucked away in temperatures below that favorable 70 – 90 °F temperature range. This isn’t to stay encounters don’t still happen in those high or low temperature extremes (relative to the range in this data, at least), they just happen significantly less frequently.
Something that I may incorporate into future data is the time at which snakes are removed relative to the month. During the summer months, there’s always a notable uptick in nocturnal removals, as snakes spend more time cruising around after sunset when temperatures are still warm. This is especially the case during heatwaves, which can cause snakes to become almost solely nocturnal. Significant heatwaves (where temperatures are in the 100s for days in a row) can allow rattlesnakes to be active essentially all night long, often capable of traveling decent distances each night should they want to. This can lead to rattlesnakes winding up in places they generally wouldn’t, as the same route traveled solely during the day would yield the same snake getting hit by a car, picked up by a bird, or more likely spotted by people.
This large rattlesnake was spotted cruising through a Fair Oaks front yard on a very warm evening in 2022.
Interesting side notes
2025 was a rather cool summer when compared to the past several years, at least in the valley, yet you’ll see it yielded the most removals in the 90 – 94 degree temperature bracket compared to the prior 3 years. Why that is, is hard to answer. Likewise, 2022 was an incredibly hot summer, with a couple of record-setting heatwaves in northern California. Yet, it yielded the least removals in that same temperature bracket.
Another oddity is the 55 – 59 degree temperature range. 2023, 2024, and 2025 had removals in that range, but 2022 did not. Why? Who knows for sure. A lot of these questions likely come down to luck/chance or probability depending on what you believe or the way you think.
How this data can be used
Clearly, humans and rattlesnakes most intersect in temperature ranges that are generally seen as comfortable (70 – 90 °F), though a sharp uptick occurs when temperatures surpass the mid-60s. This can help folks use extra caution when temperatures are expected to be anywhere in that favorable temperature range. That said, just because temperatures are outside of that favorable range, it doesn’t mean you should entirely forget about rattlesnakes. You can still find rattlesnakes above and below the favored 70 – 90 °F range, but they will more often be “in cover” in those situations, meaning the snakes will be in hiding spots they can use to stay warm or stay cool. These areas of cover can range from bushes/vegetation, rocks, tree debris, ground squirrel burrows, under homes or structures, or in other man-made materials sitting on the ground (or otherwise accessible to wildlife).
On a hot July afternoon, this very large rattlesnake found refuge in a shady front yard near a garden, where he may have also been waiting to see if a rat would run by.
Another way this data is actively being used is over on our in-house Snake Activity Forecast. The Snake Activity Forecast has been a project I’ve been running since 2022, and has been updated each week during snake season for going on 3 years now. These forecasts cover northern California, and are published at the start of each week to cover the whole week, day-by-day. Each day is broken up into 4 time brackets: morning, afternoon, evening, and overnight. Each time bracket gets a forecasted condition quality for snake activity. The higher the condition quality is, the higher potential there is for snake activity. The criteria for these condition quality levels is heavily based on in-house data and research I’ve done on weather conditions and snake activity at the surface, as well as existing studies on western rattlesnakes (crotalus oreganus), which thankfully there are quite a few of.
