August 4 in Las Vegas
Weather forecasts run out after about two weeks. For any date further out than that, the honest answer isn't a single number — it's the range Las Vegas actually delivers on this date, and how often.
On August 4, Las Vegas, NV typically reaches 105°F, but has run anywhere from 97°F to 110°F in eight years out of ten. About 90% of August 4s see no measurable precipitation.
The odds on August 4
Odds computed from the last 30 years (1996–2025).
Highs around August 4 have cooled about 0.2°F per decade since 1970 — roughly 1.1°F across the record. The figures above are shifted along that trend to 2025, so they describe today's climate rather than the average of the last 55 years.
Where this comes from: 840 daily observations from MCCARRAN INTL AP, covering 1970–2025. We pool every day within 7 days of August 4 — a single calendar date has only about 55 readings, far too few to place a 10th percentile you'd want to trust.
Why it's not a plain average: A climatology computed straight across 1970–2025 describes the middle of that period, not today, so as a statement about the present it runs cold. We fit a trend on year and shift each observation to 2025 before taking the range. The probabilities use the last 30 years instead — shifting a temperature along a trend is well defined, shifting “did it rain” is not.
What this is not: Not a forecast. It is what Las Vegas, NV has actually done on this date, which is the only defensible answer once you're past the two-week horizon where real forecasts stop. Data: NOAA NCEI GHCN-Daily.