San Marcos in Spring
In spring (March, April and May), San Marcos sees average daytime highs around 68°F and overnight lows near 53°F, with 3.8 in of rain over about 12 wet days across the season. It is the 3rd-warmest season and the 2nd-wettest season.
Over the season highs climb from about 64°F in early March to 71°F by late May. The sky is clear or mostly clear about 50% of the time across spring, and the air most often feels dry.
Spring is San Marcos's 3rd-best season to visit on our travel score. For the whole year in context, see San Marcos's year-round climate.
- Avg daytime high
- 68°F
- 3rd-warmest season
- Avg overnight low
- 53°F
- Rainfall
- 3.8 in
- 12 wet days
- Avg wind
- 4 mph
- Travel score
- 7.5
- 3rd-best season
- Months
- Mar · Apr · May
Temperature in San Marcos in Spring
Over the season highs climb from about 64°F in early March to 71°F by late May.
A typical spring day in San Marcos reaches about 68°F and drops to 53°F overnight. The warmest of the three months is May, the coolest March.
San Marcos weather by month
How the three spring months (March, April and May) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 64° / 47° | 2.9 | 5.8 | 10.1 | 6.7 |
| Feb | 64° / 48° | 3.6 | 6.8 | 10.8 | 6.4 |
| Mar | 65° / 50° | 2.2 | 6.2 | 11.7 | 6.8 |
| Apr | 68° / 53° | 1.1 | 4.1 | 12.8 | 7.5 |
| May | 71° / 56° | 0.5 | 2.1 | 13.7 | 8.1 |
| Jun | 75° / 60° | 0.1 | 0.5 | 14.1 | 9.1 |
| Jul | 80° / 65° | 0.1 | 0.4 | 14 | 8.8 |
| Aug | 82° / 66° | 0.0 | 0.2 | 13.2 | 8.5 |
| Sep | 81° / 64° | 0.1 | 0.7 | 12.2 | 8.6 |
| Oct | 76° / 59° | 0.7 | 2.6 | 11.2 | 8.7 |
| Nov | 70° / 52° | 1.1 | 3.5 | 10.3 | 7.9 |
| Dec | 64° / 47° | 2.1 | 5.1 | 9.9 | 6.8 |
Cloud cover in Spring
The sky is clear or mostly clear about 50% of the time across spring.
Chance of precipitation in Spring
San Marcos gets around 3.8 in of rain over 12 wet days across spring. The line is the day-by-day chance of measurable precipitation.
Humidity in Spring
Most of spring feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Spring
Winds average 4 mph across spring.
Sunrise & sunset in Spring
Daylight runs from about 11 h 12 min in early March to 14 hours by late May. The lit band spans sunrise to sunset each day.
Solar energy in Spring
Average shortwave solar energy reaching the ground each day across spring, about 6.5 kWh/m².
Is spring a good time to visit San Marcos?
Our two travel scores rate spring for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
spring is one of the better times to visit San Marcos for general sightseeing.
What to pack for San Marcos in Spring
From spring's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In spring, San Marcos sees daytime highs around 68°F and nights near 53°F. Pack sun protection. About 12 days see rain.
Sea temperature near San Marcos in Spring
The nearest coast averages about 62°F across spring — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 12 mi away) is warmest in August at about 71°F and coldest in January near 59°F.
It's comfortable for a long swim from Jul 5 to Oct 7 — about 3.1 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 59 | 59 | 60 | 61 | 64 | 66 | 69 | 71 | 70 | 67 | 64 | 61 |
| Comfort | Cool | Cool | Cool | Cool | Cool | Cool | Refreshing | Refreshing | Refreshing | Cool | Cool | Cool |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 59 | Cool |
| Feb | 59 | Cool |
| Mar | 60 | Cool |
| Apr | 61 | Cool |
| May | 64 | Cool |
| Jun | 66 | Cool |
| Jul | 69 | Refreshing |
| Aug | 71 | Refreshing |
| Sep | 70 | Refreshing |
| Oct | 67 | Cool |
| Nov | 64 | Cool |
| Dec | 61 | Cool |
UV index in San Marcos in Spring
Clear-sky midday UV across spring averages around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in San Marcos peaks around July 11 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 4 | 5 | 5 | 8 | 8 | 11 | 11 | 10 | 8 | 6 | 4 | 3 |
| Level | Moderate | Moderate | Moderate | Very high | Very high | Extreme | Extreme | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 4 | Moderate |
| Feb | 5 | Moderate |
| Mar | 5 | Moderate |
| Apr | 8 | Very high |
| May | 8 | Very high |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 10 | Extreme |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Air quality in San Marcos in Spring
Average fine-particle pollution (PM2.5) through the year — so you can see where spring falls, not just the annual average.
Air quality in San Marcos is worst in September — around 26 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (May, 8 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 12 | 12 | 12 | 11 | 8 | 11 | 11 | 15 | 26 | 14 | 12 | 16 |
| Level | Good | Moderate | Moderate | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 12 | Good |
| Feb | 12 | Moderate |
| Mar | 12 | Moderate |
| Apr | 11 | Good |
| May | 8 | Good |
| Jun | 11 | Good |
| Jul | 11 | Good |
| Aug | 15 | Moderate |
| Sep | 26 | Moderate |
| Oct | 14 | Moderate |
| Nov | 12 | Moderate |
| Dec | 16 | Moderate |
Where is San Marcos?
San Marcos sits at 33.1°N, 117.2°W, 581 ft above sea level, in United States. The nearest listed city is Escondido, 5.0 mi away.
Topography around San Marcos
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of San Marcos.
Within 2 miles, the terrain around San Marcos has only modest variations in elevation — a maximum elevation change of 814 ft around an average of 699 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,093 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 8,537 ft.
The land around San Marcos is covered by artificial surfaces (54%) and trees (20%) within 2 miles, trees (35%) and artificial surfaces (32%) within 10 miles, and shrubs (27%) and water (24%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for San Marcos (33.1434°, -117.1661°, elevation 581 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.