Lake Tahoe Water Temperature by Month: Warm Enough to Swim?
How warm is Lake Tahoe in the month you go? Twenty years of NASA satellite readings of the lake’s surface, month by month, and whether it is warm enough to swim.
Lake Tahoe in October: the surface averages 58 °F by day, below NOAA’s 70–78 °F comfortable rangeBelow 70 °F NOAA warns that prolonged immersion can bring on hypothermia. Most October weeks 55–62 °F by day and 57 °F at night (NASA MODIS, 2006–2025, mid-lake). Warmest: August, 67 °F; coolest: January, 40 °F. The open lake’s surface, mid-lake — not the water at the beach.
The lake by month, by day
NASA MODIS (Terra) lake-surface temperature, 2006–2025, mid-lake.
Lake Tahoe’s surface averages about 67 °F in August, its warmest month, and 40 °F in January. Even in July and August it stays a few degrees under the 70 °F at which NOAA says many people feel comfortable swimming, so a swim in Tahoe is a cold one — short, and best in the afternoon.
How to use it
Pick the month you go. The answer is the lake’s average surface temperature that month by day, the range most weeks fall in, and the night-time average, set against NOAA’s comfortable range for swimming. The bars show all twelve months, the warmest one darker. Switch to °C if you prefer.
Lake Tahoe water temperature by month
In °F (the last column °C): the average of NASA’s 8-day satellite readings of the lake surface, 2006–2025, by day (about 10:30 a.m.) and by night (about 10:30 p.m.), and the range of the middle 80% of daytime readings.
| Month | By day | Most weeks | At night | By day, °C |
|---|---|---|---|---|
| January | 40 | 37–43 | 41 | 5 |
| February | 40 | 38–43 | 40 | 5 |
| March | 41 | 38–43 | 40 | 5 |
| April | 45 | 41–49 | 42 | 7 |
| May | 51 | 45–56 | 48 | 11 |
| June | 60 | 55–64 | 56 | 15 |
| July | 67 | 64–70 | 64 | 20 |
| August | 67 | 66–69 | 65 | 20 |
| September | 65 | 62–67 | 63 | 18 |
| October | 58 | 55–62 | 57 | 14 |
| November | 50 | 46–53 | 50 | 10 |
| December | 44 | 41–46 | 43 | 7 |
The lake warms slowly: from 45 °F in April it reaches 60 °F in June and peaks in July and August, then holds on into September (65 °F) — the lake is warmer in September than in June. It never freezes over: in its coldest months, January to March, the surface stays near 40 °F.
Where the numbers come from
NASA’s MODIS instrument on the Terra satellite measures the temperature of the lake’s surface — the top fraction of a millimetre, its “skin” — from orbit, twice a day. This page uses its 8-day composites over a 3 × 3 km block in the middle of the lake, only the readings MODIS rates good, 919 composites from 2006 to 2025. NASA shares the data openly: “This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance .” It is the open lake, not the water at the beach: a calm, shallow cove can be warmer on a summer afternoon. The comfortable range is NOAA’s: “There’s no real optimal temperature, but many people feel “comfortable” swimming in water that is 70° to 78° Fahrenheit.” and “even in the summer, prolonged immersion in water temperatures below 70° Fahrenheit can produce hypothermia.”
Worked examples
A swim in July. The surface averages 67 °F by day; most July weeks 64–70 °F. Cold, but the warmest stretch of the year begins.
A September trip. 65 °F by day — warmer than June’s 60 °F, with the summer crowds gone.
Early June. 60 °F by day and 56 °F at night: paddleboarding weather more than swimming weather.
Common mistakes
- Judging the lake by the air. A 85 °F day at the beach does not make the water warm; the lake changes over weeks, not hours.
- Staying in too long. Below 70 °F a long swim can bring on hypothermia; get out before you shiver.
- Expecting July to be the warmest month. July and August are level; September is warmer than June.
Plan the trip
Read Lake Tahoe in summer, the best paddleboarding destinations and the summer bucket list. For other water, see the Great Lakes water temperature and the sea temperature at 59 beaches; for a winter trip, which ski pass covers Heavenly, Northstar or Palisades Tahoe.
FAQ
What is the water temperature of Lake Tahoe by month?
About 40 °F in January, 45 °F in April, 67 °F in July, 58 °F in October — the table above has every month.
When is Lake Tahoe warm enough to swim?
July, August and September are the warmest, 67–67 °F at the surface — still under NOAA’s 70 °F comfortable line, so short swims.
What is the warmest month at Lake Tahoe?
August, by a fraction over July: 67 °F by day.
Does Lake Tahoe freeze?
Not the open lake: its surface stays near 40 °F through January, February and March.
Why is Lake Tahoe so cold?
It is a high mountain lake and a very large, deep one, so a summer of sun warms it only slowly: it is still under 70 °F at its warmest.
Is the water warmer at the beach?
It can be, in shallow water on a calm afternoon. These are mid-lake readings from a satellite; the shore is not measured here.