San Diego records about 262mm of rain across roughly 40 wet days a year, which is a 11% chance on an average day. January is the wettest month at 48mm (18% of the annual total) and July the driest at 1mm. Local rain type: brief showers. San Diego has near-perfect weather — rain is concentrated in winter and essentially nonexistent May through September.
Chance of rain on an average day: 11%
Rainfall climatology for San Diego. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 262mm |
| Rain days per year | 40 |
| Odds on an average day | 11% |
| Wettest month | January — 48mm over 8 days |
| Driest month | July — 1mm over 1 days |
| Rain type | brief showers |
| Best dry window | May through October offers virtually guaranteed dry, sunny weather. |
| Worst rain window | January through March brings the only significant rain — still mild enough for outdoor activities between showers. |
January delivers 4700% more rain than July (48mm vs 1mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 18% of the annual total, so rain in San Diego is spread through the year — there is no season you can rely on being dry.
San Diego rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 8 days in January against 1 in July — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 48mm | 8 | 27% | 18°C |
| February | 42mm | 7 | 23% | 18°C |
| March | 40mm | 7 | 23% | 19°C |
| April | 19mm | 3 | 10% | 21°C |
| May | 5mm | 1 | 3% | 23°C |
| June | 2mm | 1 | 3% | 25°C |
| July | 1mm | 1 | 3% | 26°C |
| August | 2mm | 1 | 3% | 26°C |
| September | 5mm | 1 | 3% | 25°C |
| October | 10mm | 2 | 7% | 23°C |
| November | 27mm | 4 | 13% | 21°C |
| December | 40mm | 7 | 23% | 19°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For San Diego we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
San Diego records rain on roughly 40 days a year — about a 11% chance on any given day — totalling around 262mm.
January, with about 48mm over 8 rain days. That is 18% of the entire year's rainfall in a single month.
July is the driest month at 1mm across roughly 1 days. May through October offers virtually guaranteed dry, sunny weather.
San Diego has near-perfect weather — rain is concentrated in winter and essentially nonexistent May through September.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.