San Marcos weather in May
In May, San Marcos sees average daytime highs of 71°F and overnight lows near 56°F, with 0.5 in of rain across 2.1 wet days and about 13.7 hours of daylight. It is the 6th-warmest and 8th-wettest month of the year here.
Day-to-day highs hold fairly steady near 71°F through the month. The sky is clear or mostly clear about 55% of the time in May, and the air most often feels dry.
Daylight stretches from about 13 h 18 min at the start of May to 14 hours by month's end. Set against the rest of the year, May is San Marcos's 7th-clearest and 2nd-windiest month. For the whole year in context, see San Marcos's year-round climate.
- Daytime high
- 71°
- 6th warmest
- Overnight low
- 56°
- 7th coldest
- Rainfall
- 0.5 in
- 2.1 wet days
- Daylight
- 13 h 42 min
- 4:54 AM – 6:36 PM
- Cloud cover
- 39%
- 7th clearest
- Wind
- 5 mph
- 2nd windiest
- Solar energy
- 7.36 kWh/m²
- Travel score
- 8.1
- out of 10
San Marcos is suburb of San Diego, California, United States.
- Density
- 1,471/km²
- people per km²
- Founded
- 1963
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in May
Day-to-day highs hold fairly steady near 71°F through the month.
A typical May day in San Marcos reaches about 71°F in the afternoon and slips back to 56°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 63°F and 79°F. Set against its neighbours, May runs about 3°F warmer than April and about 5°F cooler than June.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 71 | 71 | 71 | 71 | 71 | 71 | 71 | 71 | 71 | 72 | 72 |
| Avg low (°F) | 55 | 55 | 55 | 55 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 56 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 58 | 58 | 58 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 70 | 55 |
| 2 | 70 | 55 |
| 3 | 70 | 55 |
| 4 | 70 | 55 |
| 5 | 70 | 56 |
| 6 | 70 | 56 |
| 7 | 70 | 56 |
| 8 | 70 | 56 |
| 9 | 70 | 56 |
| 10 | 70 | 56 |
| 11 | 70 | 56 |
| 12 | 70 | 56 |
| 13 | 70 | 56 |
| 14 | 70 | 56 |
| 15 | 70 | 56 |
| 16 | 70 | 56 |
| 17 | 70 | 56 |
| 18 | 70 | 56 |
| 19 | 70 | 57 |
| 20 | 70 | 57 |
| 21 | 71 | 57 |
| 22 | 71 | 57 |
| 23 | 71 | 57 |
| 24 | 71 | 57 |
| 25 | 71 | 57 |
| 26 | 71 | 57 |
| 27 | 71 | 57 |
| 28 | 71 | 57 |
| 29 | 71 | 58 |
| 30 | 72 | 58 |
| 31 | 72 | 58 |
San Marcos weather by month
How May compares with the rest of the year at a glance. May is the 6th-warmest and 8th-wettest month here — the current month is highlighted below.
| 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 May
The sky is clear or mostly clear about 55% of the time in May.
Beyond those clear spells, partly cloudy skies cover about 16% of May, with mostly cloudy or overcast conditions the remaining 29%. Skies tend to open up as the month goes on.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 69 | 69 | 69 | 68 | 68 | 68 | 68 | 68 | 68 | 68 | 68 | 70 | 70 | 70 | 70 | 71 | 71 | 71 | 71 | 72 | 72 | 72 | 73 | 73 | 73 | 75 | 75 | 75 | 75 | 77 | 77 |
| Cloudier (%) | 31 | 31 | 31 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 30 | 30 | 30 | 30 | 29 | 29 | 29 | 29 | 28 | 28 | 28 | 27 | 27 | 27 | 25 | 25 | 25 | 25 | 23 | 23 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 69 | 31 |
| 2 | 69 | 31 |
| 3 | 69 | 31 |
| 4 | 68 | 32 |
| 5 | 68 | 32 |
| 6 | 68 | 32 |
| 7 | 68 | 32 |
| 8 | 68 | 32 |
| 9 | 68 | 32 |
| 10 | 68 | 32 |
| 11 | 68 | 32 |
| 12 | 70 | 30 |
| 13 | 70 | 30 |
| 14 | 70 | 30 |
| 15 | 70 | 30 |
| 16 | 71 | 29 |
| 17 | 71 | 29 |
| 18 | 71 | 29 |
| 19 | 71 | 29 |
| 20 | 72 | 28 |
| 21 | 72 | 28 |
| 22 | 72 | 28 |
| 23 | 73 | 27 |
| 24 | 73 | 27 |
| 25 | 73 | 27 |
| 26 | 75 | 25 |
| 27 | 75 | 25 |
| 28 | 75 | 25 |
| 29 | 75 | 25 |
| 30 | 77 | 23 |
| 31 | 77 | 23 |
Chance of precipitation in May
San Marcos gets around 0.5 in of rain over 2.1 wet days in May. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 7% and peaks near 12% on the wettest days. The odds ease toward the end of the month.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 12 | 11 | 11 | 11 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 5 | 5 | 5 | 4 | 4 | 4 | 3 | 3 | 3 | 3 |
| Rain chance (%) | |
|---|---|
| 1 | 12 |
| 2 | 11 |
| 3 | 11 |
| 4 | 11 |
| 5 | 10 |
| 6 | 10 |
| 7 | 10 |
| 8 | 9 |
| 9 | 9 |
| 10 | 9 |
| 11 | 9 |
| 12 | 8 |
| 13 | 8 |
| 14 | 8 |
| 15 | 7 |
| 16 | 7 |
| 17 | 7 |
| 18 | 6 |
| 19 | 6 |
| 20 | 6 |
| 21 | 6 |
| 22 | 5 |
| 23 | 5 |
| 24 | 5 |
| 25 | 4 |
| 26 | 4 |
| 27 | 4 |
| 28 | 3 |
| 29 | 3 |
| 30 | 3 |
| 31 | 3 |
Humidity in May
Most of May feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, May lands in the dry band about 57% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 72 | 71 | 70 | 70 | 69 | 68 | 67 | 65 | 64 | 63 | 62 | 61 | 61 | 59 | 58 | 58 | 57 | 57 | 55 | 54 | 53 | 52 | 50 | 49 | 47 | 46 | 44 | 42 | 41 | 39 | 37 |
| Comfortable (%) | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 36 | 37 | 38 | 38 | 39 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 49 | 50 | 51 | 52 | 54 |
| Humid (%) | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 5 | 6 | 6 | 7 | 7 | 7 | 8 | 8 | 9 | 9 |
| Dry (%) | Comfortable (%) | Humid (%) | |
|---|---|---|---|
| 1 | 72 | 25 | 3 |
| 2 | 71 | 26 | 3 |
| 3 | 70 | 27 | 3 |
| 4 | 70 | 28 | 2 |
| 5 | 69 | 29 | 2 |
| 6 | 68 | 30 | 2 |
| 7 | 67 | 31 | 2 |
| 8 | 65 | 32 | 3 |
| 9 | 64 | 33 | 3 |
| 10 | 63 | 34 | 3 |
| 11 | 62 | 35 | 3 |
| 12 | 61 | 36 | 3 |
| 13 | 61 | 36 | 3 |
| 14 | 59 | 37 | 4 |
| 15 | 58 | 38 | 4 |
| 16 | 58 | 38 | 4 |
| 17 | 57 | 39 | 4 |
| 18 | 57 | 39 | 4 |
| 19 | 55 | 40 | 5 |
| 20 | 54 | 41 | 5 |
| 21 | 53 | 42 | 5 |
| 22 | 52 | 43 | 5 |
| 23 | 50 | 44 | 6 |
| 24 | 49 | 45 | 6 |
| 25 | 47 | 46 | 7 |
| 26 | 46 | 47 | 7 |
| 27 | 44 | 49 | 7 |
| 28 | 42 | 50 | 8 |
| 29 | 41 | 51 | 8 |
| 30 | 39 | 52 | 9 |
| 31 | 37 | 54 | 9 |
Wind in May
Winds average 5 mph in May.
Across May, daily wind ranges from about 4 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 5 | calm |
| 2 | 5 | calm |
| 3 | 5 | calm |
| 4 | 5 | calm |
| 5 | 5 | calm |
| 6 | 5 | calm |
| 7 | 5 | calm |
| 8 | 5 | calm |
| 9 | 5 | calm |
| 10 | 5 | calm |
| 11 | 5 | calm |
| 12 | 5 | calm |
| 13 | 5 | calm |
| 14 | 5 | calm |
| 15 | 5 | calm |
| 16 | 5 | calm |
| 17 | 5 | calm |
| 18 | 5 | calm |
| 19 | 5 | calm |
| 20 | 5 | calm |
| 21 | 5 | calm |
| 22 | 5 | calm |
| 23 | 5 | calm |
| 24 | 5 | calm |
| 25 | 4 | calm |
| 26 | 4 | calm |
| 27 | 4 | calm |
| 28 | 4 | calm |
| 29 | 4 | calm |
| 30 | 4 | calm |
| 31 | 4 | calm |
Sunrise & sunset in May
Daylight runs from about 13 h 18 min at the start of May to 14 hours by month's end. The lit band spans sunrise to sunset each day.
Days grow by about 42 minutes over May. Sunrise moves from 5:07 AM to 4:46 AM, and sunset from 6:25 PM to 6:46 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 13.3 | 13.3 | 13.4 | 13.4 | 13.4 | 13.4 | 13.5 | 13.5 | 13.5 | 13.6 | 13.6 | 13.6 | 13.6 | 13.7 | 13.7 | 13.7 | 13.7 | 13.8 | 13.8 | 13.8 | 13.8 | 13.8 | 13.9 | 13.9 | 13.9 | 13.9 | 13.9 | 14.0 | 14.0 | 14.0 | 14.0 |
| Sunrise (AM) | 5:07 | 5:06 | 5:05 | 5:04 | 5:03 | 5:02 | 5:01 | 5:00 | 4:59 | 4:58 | 4:58 | 4:57 | 4:56 | 4:55 | 4:54 | 4:54 | 4:53 | 4:52 | 4:52 | 4:51 | 4:50 | 4:50 | 4:49 | 4:49 | 4:48 | 4:48 | 4:47 | 4:47 | 4:47 | 4:46 | 4:46 |
| Sunset (PM) | 6:25 | 6:26 | 6:26 | 6:27 | 6:28 | 6:29 | 6:29 | 6:30 | 6:31 | 6:32 | 6:32 | 6:33 | 6:34 | 6:35 | 6:35 | 6:36 | 6:37 | 6:38 | 6:38 | 6:39 | 6:40 | 6:40 | 6:41 | 6:42 | 6:42 | 6:43 | 6:44 | 6:44 | 6:45 | 6:46 | 6:46 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 13.3 | 5:07 | 6:25 |
| 2 | 13.3 | 5:06 | 6:26 |
| 3 | 13.4 | 5:05 | 6:26 |
| 4 | 13.4 | 5:04 | 6:27 |
| 5 | 13.4 | 5:03 | 6:28 |
| 6 | 13.4 | 5:02 | 6:29 |
| 7 | 13.5 | 5:01 | 6:29 |
| 8 | 13.5 | 5:00 | 6:30 |
| 9 | 13.5 | 4:59 | 6:31 |
| 10 | 13.6 | 4:58 | 6:32 |
| 11 | 13.6 | 4:58 | 6:32 |
| 12 | 13.6 | 4:57 | 6:33 |
| 13 | 13.6 | 4:56 | 6:34 |
| 14 | 13.7 | 4:55 | 6:35 |
| 15 | 13.7 | 4:54 | 6:35 |
| 16 | 13.7 | 4:54 | 6:36 |
| 17 | 13.7 | 4:53 | 6:37 |
| 18 | 13.8 | 4:52 | 6:38 |
| 19 | 13.8 | 4:52 | 6:38 |
| 20 | 13.8 | 4:51 | 6:39 |
| 21 | 13.8 | 4:50 | 6:40 |
| 22 | 13.8 | 4:50 | 6:40 |
| 23 | 13.9 | 4:49 | 6:41 |
| 24 | 13.9 | 4:49 | 6:42 |
| 25 | 13.9 | 4:48 | 6:42 |
| 26 | 13.9 | 4:48 | 6:43 |
| 27 | 13.9 | 4:47 | 6:44 |
| 28 | 14.0 | 4:47 | 6:44 |
| 29 | 14.0 | 4:47 | 6:45 |
| 30 | 14.0 | 4:46 | 6:46 |
| 31 | 14.0 | 4:46 | 6:46 |
Solar energy in May
Average shortwave solar energy reaching the ground each day in May, about 7.36 kWh/m².
For context, solar energy here swings from a low near 3.08 kWh/m² to a high of 7.96 kWh/m² in June across the year — May's 7.36 kWh/m² sits near the top of that range.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 7.2 | 7.2 | 7.2 | 7.2 | 7.2 | 7.2 | 7.2 | 7.2 | 7.2 | 7.3 | 7.3 | 7.3 | 7.3 | 7.3 | 7.3 | 7.3 | 7.4 | 7.4 | 7.4 | 7.4 | 7.4 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.6 | 7.6 | 7.6 | 7.6 | 7.7 |
| Level | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 7.2 | Intense |
| 2 | 7.2 | Intense |
| 3 | 7.2 | Intense |
| 4 | 7.2 | Intense |
| 5 | 7.2 | Intense |
| 6 | 7.2 | Intense |
| 7 | 7.2 | Intense |
| 8 | 7.2 | Intense |
| 9 | 7.2 | Intense |
| 10 | 7.3 | Intense |
| 11 | 7.3 | Intense |
| 12 | 7.3 | Intense |
| 13 | 7.3 | Intense |
| 14 | 7.3 | Intense |
| 15 | 7.3 | Intense |
| 16 | 7.3 | Intense |
| 17 | 7.4 | Intense |
| 18 | 7.4 | Intense |
| 19 | 7.4 | Intense |
| 20 | 7.4 | Intense |
| 21 | 7.4 | Intense |
| 22 | 7.5 | Intense |
| 23 | 7.5 | Intense |
| 24 | 7.5 | Intense |
| 25 | 7.5 | Intense |
| 26 | 7.5 | Intense |
| 27 | 7.6 | Intense |
| 28 | 7.6 | Intense |
| 29 | 7.6 | Intense |
| 30 | 7.6 | Intense |
| 31 | 7.7 | Intense |
Is May a good time to visit San Marcos?
Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
May is one of the better times to visit San Marcos for general sightseeing.
What to pack for San Marcos in May
From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In May, San Marcos sees daytime highs around 71°F and nights near 56°F. Pack sun protection.
Sea temperature near San Marcos in May
The nearest coast averages about 64°F in May — 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 May
Clear-sky midday UV in May peaks around 8 (very high — sun protection essential). 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 May
Average fine-particle pollution (PM2.5) through the year — so you can see where May 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).