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July Weather in Derry Ireland

Daily high temperatures are around 64°F, rarely falling below 59°F or exceeding 70°F. The highest daily average high temperature is 65°F on July 26.

Daily low temperatures increase by 2°F, from 54°F to 56°F, rarely falling below 50°F or exceeding 60°F. The highest daily average low temperature is 56°F on July 29.

For reference, on July 26, the hottest day of the year, temperatures in Derry typically range from 56°F to 65°F, while on February 18, the coldest day of the year, they range from 40°F to 48°F.

Average High and Low Temperature in July in Derry

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on July. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in July in Derry

Average Hourly Temperature in July in DerryJul112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMJunAugcoldcoolcold
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Ocean Shores, Washington, United States (4,625 miles away) is the far-away foreign place with temperatures most similar to Derry (view comparison).

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The month of July in Derry experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 50% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 50% on July 10.

The clearest day of the month is July 10, with clear, mostly clear, or partly cloudy conditions 50% of the time.

For reference, on December 24, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 69%, while on July 6, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 50%.

Cloud Cover Categories in July in Derry

Cloud Cover Categories in July in DerryJul11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JunAugDec 2431%Dec 2431%Jul 149%Jul 149%Jul 3149%Jul 3149%Jul 1150%Jul 1150%Jul 2149%Jul 2149%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Derry, the chance of a wet day over the course of July is essentially constant, remaining around 31% throughout.

For reference, the year's highest daily chance of a wet day is 49% on January 7, and its lowest chance is 27% on April 21.

Probability of Precipitation in July in Derry

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during July in Derry is gradually increasing, starting the month at 2.3 inches, when it rarely exceeds 3.9 inches or falls below 0.8 inches, and ending the month at 2.6 inches, when it rarely exceeds 4.7 inches or falls below 0.9 inches.

The lowest average 31-day accumulation is 2.3 inches on July 3.

Average Monthly Rainfall in July in Derry

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.

Over the course of July in Derry, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 7 minutes, implying an average daily decrease of 2 minutes, 14 seconds, and weekly decrease of 15 minutes, 38 seconds.

The shortest day of the month is July 31, with 15 hours, 27 minutes of daylight and the longest day is July 1, with 16 hours, 34 minutes of daylight.

Hours of Daylight and Twilight in July in Derry

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in Derry is 5:23 AM on July 1 and the latest sunrise is 36 minutes later at 5:58 AM on July 31.

The latest sunset is 9:56 PM on July 1 and the earliest sunset is 31 minutes earlier at 9:25 PM on July 31.

Daylight saving time is observed in Derry during 2024, but it neither starts nor ends during July, so the entire month is in standard time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:18 AM and sets 16 hours, 39 minutes later, at 9:57 PM, while on December 21, the shortest day of the year, it rises at 8:40 AM and sets 7 hours, 49 minutes later, at 4:28 PM.

Sunrise & Sunset with Twilight in July in Derry

The solar day over the course of July. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in July in Derry

Solar Elevation and Azimuth in July in DerryJul112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMJunAug00101020202030304040505060000101020203030304040505060
northeastsouthwest
Solar elevation and azimuth over the course of July 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for July 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in July in Derry

Moon Rise, Set & Phases in July in DerryJul112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMJunAugJun 61:38 PMJun 61:38 PMJun 222:09 AMJun 222:09 AMJul 511:58 PMJul 511:58 PMJul 2111:18 AMJul 2111:18 AMAug 412:14 PMAug 412:14 PMAug 197:26 PMAug 197:26 PM4:36 AM4:36 AM10:41 PM10:41 PM10:20 PM10:20 PM4:53 AM4:53 AM4:05 AM4:05 AM10:25 PM10:25 PM9:51 PM9:51 PM5:01 AM5:01 AM5:30 AM5:30 AM9:50 PM9:50 PM9:07 PM9:07 PM7:04 AM7:04 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
Jul 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
24%1:50 AMENE5:34 PMWNW-9:34 AMS231,921 mi
2
14%2:09 AMNE7:02 PMNW-10:27 AMS233,338 mi
3
7%2:35 AMNE8:24 PMNW-11:22 AMS235,079 mi
4
3%3:13 AMNE9:33 PMNW-12:20 PMS237,130 mi
5
0%4:05 AMNE10:25 PMNW-1:18 PMS239,440 mi
6
0%5:13 AMNE11:02 PMNW-2:14 PMS241,909 mi
7
3%6:29 AMNE11:27 PMNW-3:05 PMS244,398 mi
8
7%7:47 AMNE11:44 PMWNW-3:53 PMS246,736 mi
9
13%9:04 AMENE11:58 PMWNW-4:37 PMS248,745 mi
10
21%10:17 AMENE--5:17 PMS250,251 mi
11
29%-12:09 AMWNW11:28 AME5:56 PMS251,107 mi
12
39%-12:18 AMW12:37 PME6:35 PMS251,202 mi
13
50%-12:28 AMW1:47 PMESE7:14 PMS250,476 mi
14
58%-12:38 AMWSW2:59 PMESE7:55 PMS248,934 mi
15
68%-12:49 AMWSW4:13 PMESE8:39 PMS246,644 mi
16
77%-1:04 AMWSW5:30 PMSE9:28 PMS243,745 mi
17
85%-1:25 AMSW6:49 PMSE10:22 PMS240,442 mi
18
92%-1:54 AMSW8:03 PMSE11:21 PMS236,991 mi
19
95%-2:39 AMSW9:05 PMSE--
20
97%-3:41 AMSW9:51 PMSE12:23 AMS233,686 mi
21
100%-5:01 AMSW10:23 PMSE1:26 AMS230,816 mi
22
99%-6:31 AMSW10:46 PMESE2:27 AMS228,621 mi
23
96%-8:03 AMWSW11:03 PMESE3:24 AMS227,252 mi
24
90%-9:33 AMWSW11:17 PME4:17 AMS226,750 mi
25
82%-11:02 AMW11:29 PME5:07 AMS227,063 mi
26
71%-12:28 PMW11:42 PMENE5:55 AMS228,061 mi
27
60%-1:55 PMWNW11:56 PMENE6:42 AMS229,583 mi
28
50%-3:22 PMWNW-7:31 AMS231,463 mi
29
37%12:13 AMENE4:49 PMNW-8:23 AMS233,561 mi
30
26%12:37 AMNE6:12 PMNW-9:17 AMS235,771 mi
31
17%1:10 AMNE7:25 PMNW-10:13 AMS238,026 mi

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in Derry is essentially constant during July, remaining around 0% throughout.

For reference, on August 7, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in July in Derry

Humidity Comfort Levels in July in DerryJul11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%JunAugJul 10%Jul 10%Jul 310%Jul 310%Jul 110%Jul 110%Jul 210%Jul 210%humidhumidcomfortablecomfortabledrydry
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Derry is essentially constant during July, remaining within 0.2 miles per hour of 12.3 miles per hour throughout.

For reference, on December 31, the windiest day of the year, the daily average wind speed is 18.1 miles per hour, while on July 25, the calmest day of the year, the daily average wind speed is 12.2 miles per hour.

The lowest daily average wind speed during July is 12.2 miles per hour on July 25.

Average Wind Speed in July in Derry

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Derry throughout July is predominantly from the west, with a peak proportion of 47% on July 18.

Wind Direction in July in Derry

Wind Direction in July in DerryJul11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%JunAugwestsouthnortheast
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Derry is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in Derry is gradually increasing during July, rising by 2°F, from 59°F to 61°F, over the course of the month.

Average Water Temperature in July in Derry

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Derry typically lasts for 11 months (337 days), from around February 1 to around January 3, rarely starting after March 18, or ending before November 29.

The month of July in Derry is reliably fully within the growing season.

Time Spent in Various Temperature Bands and the Growing Season in July in Derry

Time Spent in Various Temperature Bands and the Growing Season in July in Derrygrowing seasonJul11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JunAug100%Jul 16100%Jul 16Jul 31100%Jul 31100%coldcoolcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Derry are increasing during July, increasing by 284°F, from 359°F to 643°F, over the course of the month.

Growing Degree Days in July in Derry

Growing Degree Days in July in DerryJul1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131300°F300°F350°F350°F400°F400°F450°F450°F500°F500°F550°F550°F600°F600°F650°F650°F700°F700°F750°F750°FJunAugJul 1359°FJul 1359°FJul 31643°FJul 31643°FJul 11447°FJul 11447°FJul 21543°FJul 21543°F
The average growing degree days accumulated over the course of July, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in Derry is gradually decreasing during July, falling by 0.6 kWh, from 6.2 kWh to 5.6 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in July in Derry

Average Daily Incident Shortwave Solar Energy in July in DerryJul11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhJunAugJul 16.2 kWhJul 16.2 kWhJul 315.6 kWhJul 315.6 kWhJul 116.0 kWhJul 116.0 kWhJul 215.8 kWhJul 215.8 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

For the purposes of this report, the geographical coordinates of Derry are 51.587 deg latitude, -9.050 deg longitude, and 177 ft elevation.

The topography within 2 miles of Derry contains significant variations in elevation, with a maximum elevation change of 669 feet and an average elevation above sea level of 243 feet. Within 10 miles contains significant variations in elevation (1,102 feet). Within 50 miles contains very significant variations in elevation (3,389 feet).

The area within 2 miles of Derry is covered by grassland (73%) and cropland (16%), within 10 miles by grassland (49%) and water (31%), and within 50 miles by water (56%) and grassland (22%).

This report illustrates the typical weather in Derry, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There is only a single weather station, Cork Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Derry.

At a distance of 48 kilometers from Derry, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the station and Derry according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

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