Climate and average weather in Castro-Urdiales
In Castro-Urdiales, the summers are warm, showery, and partly cloudy and the winters are cool and partly cloudy.
Over the course of the year, the temperature in Castro-Urdiales typically varies from 8°C to 23°C, and is rarely below 5°C or above 25°C. August is the hottest month of the year, while January is the coldest.
Based on the travel score, the best time of year to visit Castro-Urdiales for warm-weather activities is from late May to early October.
- Hottest
- Aug
- 23°
- Coldest
- Jan
- 9°
- Wettest
- Nov
- 152 mm
- Driest
- Jul
- 46 mm
- Rain / yr
- 1069 mm
- 152 wet days
- Daylight
- 8.8–15.2 h
- shortest–longest
- Elevation
- 18 m
- 43.4°N
- Clearest
- Aug
- 52% cloud
Castro-Urdiales is capital of Castro-Urdiales Municipality, Spain.
- Air quality
- Good
- PM10 15.1 µg/m³ · 2019
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Castro-Urdiales 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 late May to early October.
Temperature through the year
Daily average highs and lows in Castro-Urdiales, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.4 months, from June 20 to September 30, with daily high temperatures above 20°C. The hottest month of the year in Castro-Urdiales is August, with an average high of 23°C and low of 19°C.
The cool season lasts 4.3 months, from November 25 to April 4, with daily high temperatures below 14°C. The coldest month of the year in Castro-Urdiales is January, with an average low of 9°C and high of 12°C.
Days typically run about 4°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 12 | 12 | 14 | 15 | 17 | 20 | 22 | 23 | 21 | 19 | 15 | 13 |
| Avg low (°C) | 9 | 8 | 10 | 11 | 13 | 16 | 18 | 19 | 17 | 15 | 12 | 10 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 12 | 9 |
| Feb | 12 | 8 |
| Mar | 14 | 10 |
| Apr | 15 | 11 |
| May | 17 | 13 |
| Jun | 20 | 16 |
| Jul | 22 | 18 |
| Aug | 23 | 19 |
| Sep | 21 | 17 |
| Oct | 19 | 15 |
| Nov | 15 | 12 |
| Dec | 13 | 10 |
Average hourly temperature in Castro-Urdiales
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 23°C, and coldest before dawn in January, near 9°C.
Castro-Urdiales 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 | 12° / 9° | 119 | 15 | 9.2 | 2.9 |
| Feb | 12° / 8° | 103 | 13.5 | 10.2 | 2.9 |
| Mar | 14° / 10° | 98 | 13.2 | 11.6 | 3.7 |
| Apr | 15° / 11° | 89 | 13.8 | 13.2 | 4.0 |
| May | 17° / 13° | 69 | 12.7 | 14.5 | 5.1 |
| Jun | 20° / 16° | 56 | 9.9 | 15.2 | 6.2 |
| Jul | 22° / 18° | 46 | 9.1 | 14.9 | 6.9 |
| Aug | 23° / 19° | 49 | 9.4 | 13.8 | 7.0 |
| Sep | 21° / 17° | 66 | 10.9 | 12.3 | 6.4 |
| Oct | 19° / 15° | 103 | 13.8 | 10.8 | 5.5 |
| Nov | 15° / 12° | 152 | 16.1 | 9.5 | 3.9 |
| Dec | 13° / 10° | 117 | 14.9 | 8.8 | 3.3 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Castro-Urdiales gets about 1069 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.
The wetter season lasts 5.3 months, from around Sep 28 to Mar 8, peaking in November at about 54% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 19.
November is the wettest month by volume, with 152 mm over about 16 wet days; July is the driest, with 46 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 48 | 49 | 42 | 46 | 41 | 34 | 29 | 30 | 37 | 45 | 53 | 48 |
| Rain days | 15 | 14 | 13 | 14 | 13 | 10 | 9 | 9 | 11 | 14 | 16 | 15 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 48 | 15 |
| Feb | 49 | 14 |
| Mar | 42 | 13 |
| Apr | 46 | 14 |
| May | 41 | 13 |
| Jun | 34 | 10 |
| Jul | 29 | 9 |
| Aug | 30 | 9 |
| Sep | 37 | 11 |
| Oct | 45 | 14 |
| Nov | 53 | 16 |
| Dec | 48 | 15 |
Monthly rainfall
Over a full year, Castro-Urdiales collects about 1069 mm of rain across 152 wet days — roughly 89 mm in an average month.
It doesn’t fall evenly. November is the wettest month with 152 mm, while July is the driest at just 46 mm. The three wettest months alone bring about 36% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 119 | 103 | 98 | 89 | 69 | 56 | 46 | 49 | 66 | 103 | 152 | 117 |
| Rain days | 15 | 14 | 13 | 14 | 13 | 10 | 9 | 9 | 11 | 14 | 16 | 15 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 119 | 15 |
| Feb | 103 | 14 |
| Mar | 98 | 13 |
| Apr | 89 | 14 |
| May | 69 | 13 |
| Jun | 56 | 10 |
| Jul | 46 | 9 |
| Aug | 49 | 9 |
| Sep | 66 | 11 |
| Oct | 103 | 14 |
| Nov | 152 | 16 |
| Dec | 117 | 15 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Castro-Urdiales, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around June 6 and lasts for 4.6 months, ending around October 23. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 58% of the time on average.
The cloudier part of the year begins around October 24 and lasts for 5.2 months, ending around March 29. The cloudiest month is December, when it is overcast or mostly cloudy 69% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 31 | 33 | 39 | 42 | 39 | 47 | 55 | 58 | 53 | 43 | 34 | 31 |
| Cloudier (%) | 69 | 67 | 61 | 58 | 61 | 53 | 45 | 42 | 47 | 57 | 66 | 69 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 31 | 69 |
| Feb | 33 | 67 |
| Mar | 39 | 61 |
| Apr | 42 | 58 |
| May | 39 | 61 |
| Jun | 47 | 53 |
| Jul | 55 | 45 |
| Aug | 58 | 42 |
| Sep | 53 | 47 |
| Oct | 43 | 57 |
| Nov | 34 | 66 |
| Dec | 31 | 69 |
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 11, brings about 15 h 12 min of light; the shortest, around January 1, only 8 h 48 min — a swing of roughly 6 h 24 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 9.2 | 10.2 | 11.6 | 13.2 | 14.5 | 15.2 | 14.9 | 13.8 | 12.3 | 10.8 | 9.5 | 8.8 |
| Sunrise (AM) | 8:49 | 8:21 | 7:34 | 6:37 | 5:54 | 5:37 | 5:51 | 6:23 | 6:58 | 7:34 | 8:14 | 8:45 |
| Sunset (PM) | 5:56 | 6:34 | 7:11 | 7:49 | 8:24 | 8:49 | 8:46 | 8:11 | 7:16 | 6:22 | 5:42 | 5:33 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 9.2 | 8:49 | 5:56 |
| Feb | 10.2 | 8:21 | 6:34 |
| Mar | 11.6 | 7:34 | 7:11 |
| Apr | 13.2 | 6:37 | 7:49 |
| May | 14.5 | 5:54 | 8:24 |
| Jun | 15.2 | 5:37 | 8:49 |
| Jul | 14.9 | 5:51 | 8:46 |
| Aug | 13.8 | 6:23 | 8:11 |
| Sep | 12.3 | 6:58 | 7:16 |
| Oct | 10.8 | 7:34 | 6:22 |
| Nov | 9.5 | 8:14 | 5:42 |
| Dec | 8.8 | 8:45 | 5:33 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Castro-Urdiales averages about 7 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 5 and 10 days.
The sunnier stretch runs 4.4 months, from around Jun 9 to Oct 19. The sunniest month is July, with roughly 10 sunny days (mixed).
The greyest month is January, down near 5 sunny days — about 50% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 5 | 5 | 7 | 7 | 7 | 8 | 10 | 10 | 9 | 8 | 6 | 6 |
| Sky | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Mixed | Mixed | Mixed | Mixed | Gloomy | Gloomy | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 5 | Gloomy |
| Feb | 5 | Gloomy |
| Mar | 7 | Gloomy |
| Apr | 7 | Gloomy |
| May | 7 | Gloomy |
| Jun | 8 | Mixed |
| Jul | 10 | Mixed |
| Aug | 10 | Mixed |
| Sep | 9 | Mixed |
| Oct | 8 | Gloomy |
| Nov | 6 | Gloomy |
| Dec | 6 | Gloomy |
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 Castro-Urdiales, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 4.1 months, from around June 6 to October 8. The muggiest month is July, when the air feels humid, muggy or worse about 59% of the time.
The most comfortable stretch runs from around October 9 to June 5, and April is the most comfortable month — the air is dry or comfortable 100% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 100 | 100 | 96 | 69 | 31 | 10 | 6 | 24 | 54 | 92 | 100 |
| Comfortable (%) | 0 | 0 | 0 | 4 | 28 | 41 | 32 | 28 | 35 | 35 | 8 | 0 |
| Humid (%) | 0 | 0 | 0 | 0 | 3 | 26 | 45 | 45 | 31 | 11 | 0 | 0 |
| Muggy (%) | 0 | 0 | 0 | 0 | 0 | 2 | 13 | 20 | 9 | 0 | 0 | 0 |
| Oppressive (%) | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | |
|---|---|---|---|---|---|
| Jan | 100 | 0 | 0 | 0 | 0 |
| Feb | 100 | 0 | 0 | 0 | 0 |
| Mar | 100 | 0 | 0 | 0 | 0 |
| Apr | 96 | 4 | 0 | 0 | 0 |
| May | 69 | 28 | 3 | 0 | 0 |
| Jun | 31 | 41 | 26 | 2 | 0 |
| Jul | 10 | 32 | 45 | 13 | 1 |
| Aug | 6 | 28 | 45 | 20 | 1 |
| Sep | 24 | 35 | 31 | 9 | 0 |
| Oct | 54 | 35 | 11 | 0 | 0 |
| Nov | 92 | 8 | 0 | 0 | 0 |
| Dec | 100 | 0 | 0 | 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 Castro-Urdiales is typically light breeze, near 15 km/h, and varies moderately with the seasons.
The windier part of the year lasts 6.0 months, from around Oct 22 to Apr 21. The windiest month is December, averaging about 17 km/h (light breeze).
The calmer part of the year runs from around Apr 22 to Oct 21, with August the calmest month at about 12 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 17 | 17 | 16 | 15 | 14 | 13 | 12 | 12 | 13 | 15 | 17 | 17 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | calm | light breeze | light breeze | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 17 | light breeze |
| Feb | 17 | light breeze |
| Mar | 16 | light breeze |
| Apr | 15 | light breeze |
| May | 14 | light breeze |
| Jun | 13 | light breeze |
| Jul | 12 | light breeze |
| Aug | 12 | calm |
| Sep | 13 | light breeze |
| Oct | 15 | light breeze |
| Nov | 17 | light breeze |
| Dec | 17 | light breeze |
Best time to visit Castro-Urdiales
To characterize how pleasant the weather is in Castro-Urdiales throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late September, Castro-Urdiales is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
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 Castro-Urdiales for general outdoor tourist activities is from late May to early October, with a peak score in the second week of August.
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) | 2.9 | 2.9 | 3.6 | 4.0 | 5.1 | 6.2 | 6.9 | 7.0 | 6.4 | 5.5 | 4.0 | 3.3 |
| Rating | poor | poor | fair | fair | fair | good | good | good | good | fair | fair | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 2.9 | poor |
| Feb | 2.9 | poor |
| Mar | 3.6 | fair |
| Apr | 4.0 | fair |
| May | 5.1 | fair |
| Jun | 6.2 | good |
| Jul | 6.9 | good |
| Aug | 7.0 | good |
| Sep | 6.4 | good |
| Oct | 5.5 | fair |
| Nov | 4.0 | fair |
| Dec | 3.3 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Castro-Urdiales for hot-weather activities is from mid July to mid September, with a peak score in the second week of August.
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 Castro-Urdiales, 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 23°C), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 12°C), pack a warm layer and rain gear.
In August, Castro-Urdiales sees daytime highs around 23°C and nights near 19°C. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.
Sea temperature near Castro-Urdiales
Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.
The sea offshore is warmest in August at about 22°C and coldest in February near 13°C.
It's comfortable for a long swim from Jul 11 to Sep 21 — about 2.4 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 13 | 13 | 13 | 13 | 15 | 18 | 21 | 22 | 20 | 18 | 16 | 14 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Refreshing | Refreshing | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 13 | Bracing |
| Feb | 13 | Bracing |
| Mar | 13 | Bracing |
| Apr | 13 | Bracing |
| May | 15 | Cool |
| Jun | 18 | Cool |
| Jul | 21 | Refreshing |
| Aug | 22 | Refreshing |
| Sep | 20 | Refreshing |
| Oct | 18 | Cool |
| Nov | 16 | Cool |
| Dec | 14 | Bracing |
UV index (midday) in Castro-Urdiales 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 Castro-Urdiales peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 2 | 5 | 6 | 6 | 8 | 9 | 8 | 5 | 4 | 2 | 1 |
| Level | Low | Low | Moderate | High | High | Very high | Very high | Very high | High | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 2 | Low |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 6 | High |
| Jun | 8 | Very high |
| Jul | 9 | Very high |
| Aug | 8 | Very high |
| Sep | 5 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Average hourly UV index in Castro-Urdiales
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 5 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) | 0 | 0 | 4.5 | 6.5 | 7 | 8.5 | 8.5 | 7.5 | 5.5 | 3.5 | 0 | 0 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 1.5 | 2.5 | 5 | 5 | 4.5 | 0 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 0 | 0 |
| Feb | 0 | 0 |
| Mar | 4.5 | 0 |
| Apr | 6.5 | 1.5 |
| May | 7 | 2.5 |
| Jun | 8.5 | 5 |
| Jul | 8.5 | 5 |
| Aug | 7.5 | 4.5 |
| Sep | 5.5 | 0 |
| Oct | 3.5 | 0 |
| Nov | 0 | 0 |
| Dec | 0 | 0 |
Growing season
Castro-Urdiales is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 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 | 100 | 0 |
| Dec | 100 | 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. Castro-Urdiales banks about 1,799 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) | 15 | 10 | 48 | 82 | 157 | 231 | 305 | 327 | 272 | 209 | 101 | 42 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 15 |
| Feb | 10 |
| Mar | 48 |
| Apr | 82 |
| May | 157 |
| Jun | 231 |
| Jul | 305 |
| Aug | 327 |
| Sep | 272 |
| Oct | 209 |
| Nov | 101 |
| Dec | 42 |
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.
Castro-Urdiales receives about 3.9 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 1.4 and 6.2 kWh/m².
The brighter stretch of the year lasts 6.3 months, from around Mar 16 to Sep 23. The brightest month is June, averaging about 6.1 kWh/m² (intense).
The dimmest month is December, down near 1.4 kWh/m² — roughly 77% less than the June peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 1.6 | 2.4 | 3.8 | 4.9 | 5.8 | 6.1 | 6.0 | 5.3 | 4.2 | 2.9 | 1.8 | 1.4 |
| Level | Dim | Moderate | Moderate | Bright | Bright | Intense | Intense | Bright | Bright | Moderate | Dim | Dim |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 1.6 | Dim |
| Feb | 2.4 | Moderate |
| Mar | 3.8 | Moderate |
| Apr | 4.9 | Bright |
| May | 5.8 | Bright |
| Jun | 6.1 | Intense |
| Jul | 6.0 | Intense |
| Aug | 5.3 | Bright |
| Sep | 4.2 | Bright |
| Oct | 2.9 | Moderate |
| Nov | 1.8 | Dim |
| Dec | 1.4 | Dim |
Where is Castro-Urdiales?
Castro-Urdiales sits at 43.4°N, 3.2°W, 18 m above sea level, in Spain. The nearest listed city is Santurtzi, 16 km away.
Topography around Castro-Urdiales
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Castro-Urdiales.
Within 3 km, the terrain around Castro-Urdiales has significant variations in elevation — a maximum elevation change of 455 m around an average of 60 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 851 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,676 m.
The land around Castro-Urdiales is covered by water (46%) and trees (30%) within 3 km, water (50%) and trees (35%) within 16 km, and trees (37%), water (35%) and grassland (20%) within 80 km.
Spain travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 65% of US
- price level, 2025
- GDP per capita
- $38,627
- 2025
- Happiness
- 6.5 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.7
- per 100k, 2023
- Road deaths
- 3.9
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Moderate
- EF EPI 540
- 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 Castro-Urdiales (43.3828°, -3.2204°, elevation 18 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. 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).