Climate and average weather in Piedras Negras
In Piedras Negras, the summers are humid, sweltering, fairly dry, and mostly clear and the winters are mild and mostly clear.
Over the course of the year, the temperature in Piedras Negras typically varies from 7°C to 37°C, and is rarely below 1°C or above 40°C. August is the hottest month of the year, while January is the coldest.
Based on the travel score, the best times of year to visit Piedras Negras for warm-weather activities are from early January to early April and mid October to late December.
- Hottest
- Aug
- 37°
- Coldest
- Jan
- 7°
- Wettest
- Sep
- 79 mm
- Driest
- Jan
- 25 mm
- Rain / yr
- 561 mm
- 70 wet days
- Daylight
- 10.2–13.8 h
- shortest–longest
- Elevation
- 223 m
- 28.7°N
- Clearest
- Oct
- 38% cloud
Piedras Negras is municipal seat of Piedras Negras, State of Coahuila, Mexico.
- Founded
- 1850
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Piedras Negras weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early January to early April.
Temperature through the year
Daily average highs and lows in Piedras Negras, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 4.4 months, from May 12 to September 21, with daily high temperatures above 33°C. The hottest month of the year in Piedras Negras is August, with an average high of 37°C and low of 26°C.
The cool season lasts 2.8 months, from November 24 to February 15, with daily high temperatures below 22°C. The coldest month of the year in Piedras Negras is January, with an average low of 7°C and high of 19°C.
Days typically run about 12°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 19 | 22 | 26 | 30 | 33 | 36 | 37 | 37 | 34 | 29 | 23 | 19 |
| Avg low (°C) | 7 | 10 | 14 | 18 | 22 | 25 | 26 | 26 | 23 | 18 | 12 | 8 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 19 | 7 |
| Feb | 22 | 10 |
| Mar | 26 | 14 |
| Apr | 30 | 18 |
| May | 33 | 22 |
| Jun | 36 | 25 |
| Jul | 37 | 26 |
| Aug | 37 | 26 |
| Sep | 34 | 23 |
| Oct | 29 | 18 |
| Nov | 23 | 12 |
| Dec | 19 | 8 |
How hot and cold Piedras Negras really feels
The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.
On the hottest afternoons, once humidity is folded in, Piedras Negras feels like about 41°C (around August 9). About 153 days a year carry some heat stress, and 77 of them tip into dangerous heat (feels-like above 39°C), peaking in August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 19 | 22 | 26 | 30 | 34 | 39 | 40 | 40 | 35 | 29 | 23 | 19 |
| Air high (°C) | 19 | 22 | 26 | 30 | 33 | 36 | 37 | 37 | 34 | 29 | 23 | 19 |
| Feels-like low (°C) | 5 | 9 | 14 | 18 | 22 | 25 | 26 | 26 | 23 | 18 | 12 | 6 |
| Air low (°C) | 7 | 10 | 14 | 18 | 22 | 25 | 26 | 26 | 23 | 18 | 12 | 8 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 19 | 19 | 5 | 7 |
| Feb | 22 | 22 | 9 | 10 |
| Mar | 26 | 26 | 14 | 14 |
| Apr | 30 | 30 | 18 | 18 |
| May | 34 | 33 | 22 | 22 |
| Jun | 39 | 36 | 25 | 25 |
| Jul | 40 | 37 | 26 | 26 |
| Aug | 40 | 37 | 26 | 26 |
| Sep | 35 | 34 | 23 | 23 |
| Oct | 29 | 29 | 18 | 18 |
| Nov | 23 | 23 | 12 | 12 |
| Dec | 19 | 19 | 6 | 8 |
Average hourly temperature in Piedras Negras
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 37°C, and coldest before dawn in January, near 7°C.
Piedras Negras weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 19° / 7° | 25 | 4.4 | 10.4 | 7.1 |
| Feb | 22° / 10° | 27 | 4.5 | 11 | 7.6 |
| Mar | 26° / 14° | 43 | 5.6 | 11.8 | 7.5 |
| Apr | 30° / 18° | 48 | 6.1 | 12.7 | 5.5 |
| May | 33° / 22° | 74 | 8.3 | 13.4 | 3.5 |
| Jun | 36° / 25° | 46 | 6.1 | 13.8 | 2.1 |
| Jul | 37° / 26° | 50 | 5.9 | 13.6 | 1.6 |
| Aug | 37° / 26° | 46 | 4.6 | 13 | 1.6 |
| Sep | 34° / 23° | 79 | 8.3 | 12.2 | 3.5 |
| Oct | 29° / 18° | 60 | 6.5 | 11.3 | 6.2 |
| Nov | 23° / 12° | 36 | 4.8 | 10.6 | 7.8 |
| Dec | 19° / 8° | 27 | 4.5 | 10.2 | 7.1 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Piedras Negras gets about 561 mm of precipitation a year. On a typical day the chance of rain is some rain, but that rises and falls sharply with the seasons.
The wetter season lasts 2.0 months, from around Aug 24 to Oct 24, peaking in September at about 30% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Aug 7.
September is the wettest month by volume, with 79 mm over about 8 wet days; January is the driest, with 25 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 14 | 15 | 18 | 21 | 26 | 21 | 18 | 16 | 27 | 21 | 16 | 14 |
| Rain days | 4 | 5 | 6 | 6 | 8 | 6 | 6 | 5 | 8 | 7 | 5 | 5 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 14 | 4 |
| Feb | 15 | 5 |
| Mar | 18 | 6 |
| Apr | 21 | 6 |
| May | 26 | 8 |
| Jun | 21 | 6 |
| Jul | 18 | 6 |
| Aug | 16 | 5 |
| Sep | 27 | 8 |
| Oct | 21 | 7 |
| Nov | 16 | 5 |
| Dec | 14 | 5 |
Monthly rainfall
Over a full year, Piedras Negras collects about 561 mm of rain across 70 wet days — roughly 47 mm in an average month.
It doesn’t fall evenly. September is the wettest month with 79 mm, while January is the driest at just 25 mm. The three wettest months alone bring about 38% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 25 | 27 | 43 | 48 | 74 | 46 | 50 | 46 | 79 | 60 | 36 | 27 |
| Rain days | 4 | 5 | 6 | 6 | 8 | 6 | 6 | 5 | 8 | 7 | 5 | 5 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 25 | 4 |
| Feb | 27 | 5 |
| Mar | 43 | 6 |
| Apr | 48 | 6 |
| May | 74 | 8 |
| Jun | 46 | 6 |
| Jul | 50 | 6 |
| Aug | 46 | 5 |
| Sep | 79 | 8 |
| Oct | 60 | 7 |
| Nov | 36 | 5 |
| Dec | 27 | 5 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Piedras Negras, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.
The clearer part of the year begins around May 24 and lasts for 5.3 months, ending around October 30. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 76% of the time on average.
The cloudier part of the year begins around October 31 and lasts for 6.7 months, ending around May 23. The cloudiest month is February, when it is overcast or mostly cloudy 45% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 56 | 55 | 56 | 60 | 62 | 74 | 73 | 76 | 71 | 70 | 61 | 58 |
| Cloudier (%) | 44 | 45 | 44 | 40 | 38 | 26 | 27 | 24 | 29 | 30 | 39 | 42 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 56 | 44 |
| Feb | 55 | 45 |
| Mar | 56 | 44 |
| Apr | 60 | 40 |
| May | 62 | 38 |
| Jun | 74 | 26 |
| Jul | 73 | 27 |
| Aug | 76 | 24 |
| Sep | 71 | 29 |
| Oct | 70 | 30 |
| Nov | 61 | 39 |
| Dec | 58 | 42 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 7, brings about 13 h 48 min of light; the shortest, around January 1, only 10 h 12 min — a swing of roughly 3 h 36 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 10.4 | 11.0 | 11.8 | 12.7 | 13.4 | 13.8 | 13.6 | 13.0 | 12.2 | 11.3 | 10.6 | 10.2 |
| Sunrise (AM) | 7:41 | 7:27 | 6:58 | 6:22 | 5:56 | 5:48 | 5:58 | 6:15 | 6:31 | 6:48 | 7:11 | 7:33 |
| Sunset (PM) | 6:02 | 6:26 | 6:45 | 7:03 | 7:21 | 7:37 | 7:38 | 7:17 | 6:41 | 6:06 | 5:44 | 5:44 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 10.4 | 7:41 | 6:02 |
| Feb | 11.0 | 7:27 | 6:26 |
| Mar | 11.8 | 6:58 | 6:45 |
| Apr | 12.7 | 6:22 | 7:03 |
| May | 13.4 | 5:56 | 7:21 |
| Jun | 13.8 | 5:48 | 7:37 |
| Jul | 13.6 | 5:58 | 7:38 |
| Aug | 13.0 | 6:15 | 7:17 |
| Sep | 12.2 | 6:31 | 6:41 |
| Oct | 11.3 | 6:48 | 6:06 |
| Nov | 10.6 | 7:11 | 5:44 |
| Dec | 10.2 | 7:33 | 5:44 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Piedras Negras averages about 15 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 11 and 19 days.
The sunnier stretch runs 1.9 months, from around Sep 12 to Nov 7. The sunniest month is September, with roughly 16 sunny days (bright).
The greyest month is May, down near 12 sunny days — about 28% fewer than the September peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 14 | 13 | 13 | 14 | 12 | 15 | 17 | 17 | 16 | 18 | 15 | 15 |
| Sky | Mixed | Mixed | Mixed | Mixed | Mixed | Bright | Bright | Bright | Bright | Bright | Bright | Mixed |
| Sunny days | Sky | |
|---|---|---|
| Jan | 14 | Mixed |
| Feb | 13 | Mixed |
| Mar | 13 | Mixed |
| Apr | 14 | Mixed |
| May | 12 | Mixed |
| Jun | 15 | Bright |
| Jul | 17 | Bright |
| Aug | 17 | Bright |
| Sep | 16 | Bright |
| Oct | 18 | Bright |
| Nov | 15 | Bright |
| Dec | 15 | Mixed |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
In Piedras Negras, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 5.7 months, from around April 26 to October 17. The muggiest month is August, when the air feels humid, muggy or worse about 98% of the time.
The most comfortable stretch runs from around October 18 to April 25, and January is the most comfortable month — the air is dry or comfortable 97% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 91 | 83 | 61 | 42 | 12 | 1 | 0 | 0 | 10 | 33 | 62 | 86 |
| Comfortable (%) | 6 | 11 | 17 | 16 | 9 | 4 | 2 | 2 | 8 | 16 | 18 | 8 |
| Humid (%) | 3 | 6 | 18 | 22 | 24 | 16 | 20 | 19 | 16 | 19 | 14 | 5 |
| Muggy (%) | 0 | 0 | 3 | 18 | 44 | 51 | 53 | 57 | 36 | 23 | 7 | 1 |
| Oppressive (%) | 0 | 0 | 0 | 1 | 12 | 28 | 25 | 21 | 30 | 9 | 1 | 0 |
| Miserable (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| Jan | 91 | 6 | 3 | 0 | 0 | 0 |
| Feb | 83 | 11 | 6 | 0 | 0 | 0 |
| Mar | 61 | 17 | 18 | 3 | 0 | 0 |
| Apr | 42 | 16 | 22 | 18 | 1 | 0 |
| May | 12 | 9 | 24 | 44 | 12 | 0 |
| Jun | 1 | 4 | 16 | 51 | 28 | 0 |
| Jul | 0 | 2 | 20 | 53 | 25 | 0 |
| Aug | 0 | 2 | 19 | 57 | 21 | 0 |
| Sep | 10 | 8 | 16 | 36 | 30 | 1 |
| Oct | 33 | 16 | 19 | 23 | 9 | 0 |
| Nov | 62 | 18 | 14 | 7 | 1 | 0 |
| Dec | 86 | 8 | 5 | 1 | 0 | 0 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Across the year, average wind speed in Piedras Negras is typically light breeze, near 14 km/h, and varies moderately with the seasons.
The windier part of the year lasts 5.7 months, from around Mar 5 to Aug 25. The windiest month is June, averaging about 17 km/h (light breeze).
The calmer part of the year runs from around Aug 26 to Mar 4, with December the calmest month at about 12 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 12 | 13 | 14 | 16 | 16 | 17 | 16 | 14 | 12 | 13 | 12 | 12 |
| Feels | calm | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 12 | calm |
| Feb | 13 | light breeze |
| Mar | 14 | light breeze |
| Apr | 16 | light breeze |
| May | 16 | light breeze |
| Jun | 17 | light breeze |
| Jul | 16 | light breeze |
| Aug | 14 | light breeze |
| Sep | 12 | light breeze |
| Oct | 13 | light breeze |
| Nov | 12 | light breeze |
| Dec | 12 | calm |
Best time to visit Piedras Negras
To characterize how pleasant the weather is in Piedras Negras throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around mid January, Piedras Negras is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Piedras Negras for general outdoor tourist activities is from mid October to early April, with a peak score in the last week of February.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 7.1 | 7.6 | 7.4 | 5.5 | 3.5 | 2.1 | 1.6 | 1.7 | 3.5 | 6.2 | 7.8 | 7.2 |
| Rating | good | ideal | good | good | fair | poor | poor | poor | poor | good | ideal | good |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 7.1 | good |
| Feb | 7.6 | ideal |
| Mar | 7.4 | good |
| Apr | 5.5 | good |
| May | 3.5 | fair |
| Jun | 2.1 | poor |
| Jul | 1.6 | poor |
| Aug | 1.7 | poor |
| Sep | 3.5 | poor |
| Oct | 6.2 | good |
| Nov | 7.8 | ideal |
| Dec | 7.2 | good |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best times of year to visit Piedras Negras for hot-weather activities run from late February to late May and again from mid September to mid November, with a peak score in the third week of October.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Piedras Negras, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
For a warm-season trip around August (highs near 37°C), the essentials are light clothes and sun protection. In the cold season around January (highs near 19°C), pack a warm layer.
In August, Piedras Negras sees daytime highs around 37°C and nights near 26°C. Pack light clothes and sun protection. About 5 days see rain.
UV index (midday) in Piedras Negras by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Piedras Negras peaks around July 14 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 18 at about 4 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 5 | 6 | 7 | 10 | 10 | 11 | 11 | 11 | 9 | 7 | 5 | 4 |
| Level | Moderate | High | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 5 | Moderate |
| Feb | 6 | High |
| Mar | 7 | Very high |
| Apr | 10 | Very high |
| May | 10 | Extreme |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 11 | Extreme |
| Sep | 9 | Very high |
| Oct | 7 | High |
| Nov | 5 | Moderate |
| Dec | 4 | Moderate |
Average hourly UV index in Piedras Negras
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in July the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 4 | 5.5 | 6.5 | 7.5 | 8 | 8.5 | 8.5 | 8 | 7 | 6 | 4.5 | 3.5 |
| UV ≥ 6 (h/day) | 0 | 1 | 3 | 5 | 5.5 | 6 | 6 | 6 | 4.5 | 2.5 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 4 | 0 |
| Feb | 5.5 | 1 |
| Mar | 6.5 | 3 |
| Apr | 7.5 | 5 |
| May | 8 | 5.5 |
| Jun | 8.5 | 6 |
| Jul | 8.5 | 6 |
| Aug | 8 | 6 |
| Sep | 7 | 4.5 |
| Oct | 6 | 2.5 |
| Nov | 4.5 | 0 |
| Dec | 3.5 | 0 |
Air quality in Piedras Negras by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.
Air quality in Piedras Negras is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (February, 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) | 9 | 8 | 9 | 10 | 16 | 16 | 18 | 13 | 12 | 9 | 10 | 11 |
| Level | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 9 | Good |
| Feb | 8 | Good |
| Mar | 9 | Good |
| Apr | 10 | Good |
| May | 16 | Moderate |
| Jun | 16 | Moderate |
| Jul | 18 | Moderate |
| Aug | 13 | Moderate |
| Sep | 12 | Good |
| Oct | 9 | Good |
| Nov | 10 | Good |
| Dec | 11 | Good |
Growing season
Piedras Negras is mild enough that a frost-free day stays more likely than not even in midwinter.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 95 | 98 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 99 | 96 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 95 | 0 |
| Feb | 98 | 0 |
| Mar | 100 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 99 | 0 |
| Dec | 96 | 0 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Piedras Negras banks about 4,790 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 100 | 165 | 304 | 417 | 545 | 616 | 664 | 667 | 548 | 420 | 234 | 110 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 100 |
| Feb | 165 |
| Mar | 304 |
| Apr | 417 |
| May | 545 |
| Jun | 616 |
| Jul | 664 |
| Aug | 667 |
| Sep | 548 |
| Oct | 420 |
| Nov | 234 |
| Dec | 110 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Piedras Negras receives about 5.0 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 3.0 and 6.9 kWh/m².
The brighter stretch of the year lasts 6.3 months, from around Mar 21 to Sep 28. The brightest month is July, averaging about 6.9 kWh/m² (intense).
The dimmest month is December, down near 3.1 kWh/m² — roughly 55% less than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 3.3 | 4.0 | 4.9 | 5.9 | 6.1 | 6.7 | 6.9 | 6.6 | 5.3 | 4.3 | 3.3 | 3.0 |
| Level | Moderate | Bright | Bright | Bright | Intense | Intense | Intense | Intense | Bright | Bright | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 3.3 | Moderate |
| Feb | 4.0 | Bright |
| Mar | 4.9 | Bright |
| Apr | 5.9 | Bright |
| May | 6.1 | Intense |
| Jun | 6.7 | Intense |
| Jul | 6.9 | Intense |
| Aug | 6.6 | Intense |
| Sep | 5.3 | Bright |
| Oct | 4.3 | Bright |
| Nov | 3.3 | Moderate |
| Dec | 3.0 | Moderate |
Where is Piedras Negras?
Piedras Negras sits at 28.7°N, 100.5°W, 223 m above sea level, in Mexico. The nearest listed city is Eagle Pass, 3.0 km away.
Topography around Piedras Negras
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Piedras Negras.
Within 3 km, the terrain around Piedras Negras has only modest variations in elevation — a maximum elevation change of 52 m around an average of 227 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 110 m; within 80 km, significant variations in elevation — a maximum elevation change of 586 m.
The land around Piedras Negras is covered by artificial surfaces (60%) within 3 km, shrubs (70%) within 16 km, and shrubs (89%) within 80 km.
Mexico travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type A / B
- 120 / 127 V · 60 Hz
- Prices
- ≈ 54% of US
- price level, 2025
- GDP per capita
- $13,889
- 2025
- Happiness
- 7.0 / 10
- World Happiness, 2025
- Safe drinking water
- 43%
- of population, 2024
- Homicide rate
- 24.9
- per 100k, 2023
- Road deaths
- 12.8
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Very low
- EF EPI 440
- 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 Piedras Negras (28.7001°, -100.5235°, elevation 223 m), 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. 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).