Kern River temperature summary

From a general rafting standpoint, the water on the Lower Kern River is warm and you will not need a wetsuit. The water on the Upper Kern River can be chilly though, and you may need a wetsuit in March, April and May. In June and July, it can be warm enough that one is not needed. Again, this is giving an answer with a broad paintbrush, with more exact information below.

Upper Kern River water temperature

When I first started digging into this question, I was pretty confident I would be able to find a USGS gauge that was tracking water temperature. What’s interesting, is that none currently exists, which I would say is pretty unusual for a river that sees this much use. After plenty of searching, I was able to find an old gauge that took daily Upper Kern water temperature readings from 1980 through 1988. This gauge was located near Kernville. I’ve averaged and summarised the data below by month. It is my belief that while this data is considered old, that current water temperatures on the Upper Kern should be close to what is listed below. If anything, current water temperatures will be slightly higher.

MonthUpper Kern River – Average Water Temperature (Fahrenheit)

Lower Kern River water temperature

Despite Lake Isabella being filled by the chilly Upper Kern River, the lake is pretty warm. It’s a shallow lake, and during the summer months, it gets hot around here, with many weeks hanging around 100 degrees. This translates to a lake that’s easy to warm, and then as they release that water, a comfortable Lower Kern River.

When I found that old river gauge on the Upper Kern, I was confident that I would find one on the Lower Kern as well. It’s odd, but nothing ever surfaced. Even after asking around, no one had any good idea. I knew the water was warm, but any sense of exactly how warm, I had no clue and it appeared no one else had ever bothered to measure it. So I’ve decided to measure it. I bought a digital reader, and as often as I can, I’ll be measuring it at the same place and recording the water temperature. Sure, it’s not the most scientific method, but at least it’s some sort of data that we can look at.

DateTime (approximate)Lower Kern River – Water Temperature (Fahrenheit)LocationCFS
6/21/2020Morning65.8Slippery Rock837
6/22/2020Morning65.1Delonegha Bridge987
6/24/2020Afternoon69.8Delonegha Bridge1144
7/4/2020Morning66.6Delonegha Bridge1072
10/12/2021Afternoon61.3Slippery Rock116
3/17/2022Morning49.5Hobo takeout265

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  1. Hi Matt
    Can you tell me given the lack of rain if rafting the upper Kings River would be a good idea in mid-late June? Or some other time before or after?
    Thank you

    1. Hi Kiely, thank you for the comment. The Kings river only has one rafting section, and I think they’ll be running this year. I would get in touch with Jeb at Kings River Expeditions, he will know for sure. You may have meant the Upper KERN though, and for that, it’s too early to tell on our 2022 season for mid to late June. I think it’s possible but we’ll definitely have low water. The best time to go this year on the Upper Kern will be in the May timeframe. Keep in mind that the Lower Kern (different section of the Kern river) will be running June and July.

  2. Hi Matt,
    We’re thinking of booking a rafting trip on the Kern in mid August. We have a 7 yr old and a 10 yr old, given the amount of water this year, is it safe for them to raft? Is there an age limit?
    Thanks, Anna

    1. Hi Anna, unfortunately your 7 year old is too young to join us on a rafting trip but the Kernville Rapid Run is a really good fit for your 10 year old. (That trip has a minimum age of 8 years old.) The KRR is fun and safe at low and high flows.

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