San Marcos, TX Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from San Marcos's primary NOAA station, SAN MARCOS.
The climate verdict for San Marcos
San Marcos, Texas has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 69°F. It scores 97/100 for climate comfort (excellent), putting it in the top third of station-mapped location scores and exceeding 97% of them.
- 69°F
- annual average temperature (NOAA normal)
- 97/100
- comfort score, above 97% of station-mapped location scores
- 36.5"
- precipitation, annual total
- 274 days
- frost-free days per growing season
San Marcos: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00417983 · San Marcos, TX 69°F mean · 36.5" precip
TEMP-MILD · RANK-WARM · PHOTO-FINISH · PRCP-MID · SWING-MID · COMF-TOP · LOAD-MIX · STN-1 · BOOK-FULL
- TEMP-MILD 69°F
- RANK-WARM #6,449
- PHOTO-FINISH ≈ Livingston
- PRCP-MID 36.5"
- SWING-MID 35°F
- COMF-TOP 97/100
- LOAD-MIX H/C balanced
- STN-1 USC00417983
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Livingston, TX (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every TX station list.
- San Marcos (this station) 69°F
- Cold Baton Rouge Ryan, LA 69°F
- Hot St Bernard, LA 69°F
- Near Livingston, TX 69°F
- Near Pensacola, FL 69°F
San Marcos sits in Texas, the #4 hottest U.S. state at 66.2°F statewide annual average - see all 50 hottest states ranked by NOAA normals
Climate Living Index · San Marcos
San Marcos: 87/100 · grade A
San Marcos publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for San Marcos, not an official NOAA rating. Rankings still use Comfort Score 97/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Frost-free season | 274 days/year | 96/100 · A |
| Annual temperature balance | 68.6°F · 1.1° from 67.5°F | 95/100 · A |
| Precipitation balance | 36.5 in · 1.5 from 35 in | 93/100 · A |
| Snowfall burden | 0.0 inches/year | 90/100 · A |
| Normal heat + freeze calendar | 110 calendar days | 70/100 · B |
San Marcos · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
San Marcos is a temperate Köppen climate: Cfa
Coldest-month mean 50.6°F and warmest-month mean 85.2°F place this station in temperate, no dry season, hot summer climates (Cfa). Class Cfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, no dry season, hot summer.
- Köppen code
- Cfa
- Group
- Temperate
- Warmest month
- 85.2°F
- Coldest month
- 50.6°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · balanced station
Where San Marcos sits across the climate record
Three NOAA fields for San Marcos's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Top 6% warmest
- Among 6,861 stations, San Marcos sits in the warmer third of annual means.
- Annual precipitation
- 51st percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Narrower than 83%
- Warmest-to-coldest month gap for San Marcos is compact versus 6,861 complete station-years.
How San Marcos compares across U.S. station-mapped locations
San Marcos's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
97 Top 3% score exceeds 97% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). Below this entry.
- 70–80: 650 station-mapped locations (11%). Below this entry.
- 80–90: 921 station-mapped locations (15%). Below this entry.
- 90–100: 564 station-mapped locations (9%). This entry sits in this band.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
San Marcos's measured station temperature trend
MethodologyAcross 53 complete annual observations from 1909 to 2025, SAN MARCOS warmed at a fitted rate of 0.13°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- San Marcos primary station fitted change +0.13 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 62°F (17°C) | 39°F (4°C) | 51°F (10°C) | 2.4" | 0.0" | 6.9 | 0.0 |
| February | 67°F (19°C) | 42°F (6°C) | 55°F (13°C) | 1.7" | 0.0" | 4.4 | 0.2 |
| March | 73°F (23°C) | 50°F (10°C) | 61°F (16°C) | 2.8" | 0.0" | 1.2 | 0.3 |
| April | 80°F (27°C) | 56°F (13°C) | 68°F (20°C) | 3.2" | 0.0" | 0.0 | 1.8 |
| May | 86°F (30°C) | 65°F (18°C) | 76°F (24°C) | 4.5" | 0.0" | 0.0 | 9.7 |
| June | 92°F (34°C) | 72°F (22°C) | 82°F (28°C) | 3.6" | 0.0" | 0.0 | 23.6 |
| July | 96°F (35°C) | 73°F (23°C) | 85°F (29°C) | 2.2" | 0.0" | 0.0 | 28.5 |
| August | 97°F (36°C) | 74°F (23°C) | 85°F (30°C) | 2.6" | 0.0" | 0.0 | 28.6 |
| September | 91°F (33°C) | 69°F (20°C) | 80°F (26°C) | 4.0" | 0.0" | 0.0 | 19.1 |
| October | 82°F (28°C) | 58°F (15°C) | 70°F (21°C) | 4.4" | 0.0" | 0.0 | 4.9 |
| November | 72°F (22°C) | 48°F (9°C) | 60°F (16°C) | 2.7" | 0.0" | 1.7 | 0.0 |
| December | 64°F (18°C) | 41°F (5°C) | 52°F (11°C) | 2.4" | 0.0" | 5.6 | 0.0 |
The year, day by day
The year in San Marcos runs from a mild 39°F around January 5 to 98°F at the peak near August 7, and the normal low never reaches freezing on any date in the record.
When the heat sits
Normal highs reach 90°F from May 31 through September 17, covering 110 dates. The broader mild season, normal highs of 70°F or more, runs March 4 to November 19.
This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.
No freezing date
Not one calendar date in the 1991–2020 record carries a normal low at or below 32°F. The coldest normal low of the year is 39°F around January 5.
Where the wet dates fall
The likeliest wet date is March 14, when 26% of years recorded at least a hundredth of an inch. The driest is August 1 at 14%. Summed across the calendar, that is about 81 wet dates a year.
The widest day
February 8 carries the biggest normal gap between afternoon and dawn, 24°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for San Marcos.
Where San Marcos Stands Nationally
Summers here run among the most heat-heavy normals calendars in the country: on about 110 days a year the normal daily high itself reaches 90°F — a count fewer than one station in ten exceeds.
San Marcos earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
7.1 days with precipitation
7.4 days with precipitation
8.1 days with precipitation
6.5 days with precipitation
8.0 days with precipitation
6.3 days with precipitation
5.2 days with precipitation
4.8 days with precipitation
7.2 days with precipitation
6.0 days with precipitation
6.1 days with precipitation
7.6 days with precipitation
San Marcos spreads its precipitation across the year
Neither half of the year dominates here: June through August take 23% of the annual total and December through February 18%, with neither reaching the 35% that would mark a distinct wet season. San Marcos has no dry season to plan around, though it does carry a 34.6°F seasonal spread.
The gap between the wettest and driest month still matters: May averages 4.5" and February 1.7". The three wettest months together take 35% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
When it rains in San Marcos, it arrives in quantity
36.6" of precipitation falls across only about 80 wet days here, averaging 0.46 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 80 a year, 22% of all days
- Average depth per wet day
- 0.46 inches
- Most wet days
- March, about 8
- Fewest wet days
- August, about 5
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
San Marcos's record shows no measurable snowfall
This station measured snowfall across the 1991-2020 period and recorded none: the annual normal is 0.0 inches. That is a measured zero rather than missing data, which is a meaningful distinction here , most stations in the database simply do not report snow at all, and those pages say nothing about it.
A thirty-year normal of zero describes the typical year at this station. It is not a claim that snow has never fallen in the area.
Frost Dates & Growing Season
First Fall Freeze
November 29
50% probability date
Last Spring Freeze
February 28
50% probability date
Growing Season
274 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
1,620
Higher = more heating needed
Cooling Degree Days
2,974
Higher = more cooling needed
Warmest Month
August
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside TX closest to San Marcos on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (69°F here).
- Pensacola, FL 69°F · 0.0°F off
- Biloxi, MS 69°F · 0.1°F off
- Glen St Mary, FL 69°F · 0.1°F off
- Green Valley, AZ 68°F · 0.2°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (36.5" here), excluding temperature-peer places.
- Des Moines, IA 36.5" · 0.0" off
- Kingfisher, OK 36.5" · 0.0" off
- Mullan, ID 36.6" · 0.0" off
- Greenfield, IA 36.5" · 0.0" off
Data-derived climate profile
How San Marcos's climate pattern fits together
mixed demand · moderate · mid swing
August and January mark the typical warm and cold ends of the calendar in San Marcos's middle-range seasonal profile. The measured spread is 34.6°F. The annual average is 69°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Heating and cooling both register in San Marcos's normal, at 1,620 and 2,974 degree days respectively. Neither total exceeds the other by more than two to one, so the record is better read as a mixed-demand calendar than as heating-led or cooling-led.
The frost-free window extends for about 274 days. That is a long calendar measure, but it is not a forecast and does not combine heat, rainfall, soil, or local elevation into a planting recommendation.
San Marcos's 36.5 inches of annual precipitation falls in PlainClimate's middle band, so “wet” or “dry” is not the leading description. Recorded annual snowfall is negligible. Temperature balance and the calendar distribution carry more information than the annual moisture label alone.
These labels group NOAA 1991-2020 normals from San Marcos's primary station, where heating and cooling demand are close enough that neither season sets the character on its own. On a balanced station like San Marcos, the bands are descriptive ranges rather than an official NOAA classification or a forecast.
Questions about San Marcos's climate
How much rain does San Marcos get? ▼
How many days above 90°F does San Marcos get? ▼
How much energy does heating and cooling require in San Marcos? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from San Marcos's primary station: SAN MARCOS (USC00417983). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 4865600). Match rule for San Marcos: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for San Marcos comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.