Climate averages 1991–2020

Derry weather
in May.

A cool, moderately wet month: the 5th warmest and the 5th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 13.8°C Daytime mean, May
Average low 7.6°C Night-time mean, May
Rainfall 78 mm 15 days with ≥1 mm
Daylight 16 h Sunrise to sunset, per day
Every month in Derry · average highYear overview

May is a cool month in Derry: daytime highs average 13.8°C and nights cool to about 7.6°C. By daytime temperature it is the 5th warmest of the 12 months.

Expect about 78 mm of rain on roughly 15 days, which makes May a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 16 h 06 min on an average May day.

The nearest other city in this atlas is Lisburn (97 km away). In May its highs average 13.8°C, about as warm as Derry, with 70 mm of rain.

Among the 143 cities listed in the United Kingdom, Derry ranks joint 127th of 143 for the warmest May highs and joint 137th of 143 for the driest May (rainfall, lowest first). The mean May high of those 143 cities is 15.2°C; Derry is 1.4°C cooler than that mean.

From May to June, average highs rise by 2.1°C to 15.9°C, and monthly rainfall rises from 78 mm to 87 mm.

The annual picture

May in context

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. 05101520 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 1000

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Derry climate table

1991–2020
Monthly climate averages for Derry, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 7.1°C3.0°C3.0°C8716.47.88 h
February 7.5°C3.0°C3.0°C7615.19.610 h
March 9.0°C3.7°C3.7°C7515.611.812 h
April 11.1°C5.1°C5.1°C7415.414.114 h
May, selected 13.8°C7.6°C7.6°C7815.116.116 h
June 15.9°C10.2°C10.2°C8715.517.317 h
July 17.3°C11.9°C11.9°C9316.816.817 h
August 17.1°C11.9°C11.9°C9416.715.015 h
September 15.4°C10.4°C10.4°C7514.212.813 h
October 12.3°C8.0°C8.0°C8815.510.511 h
November 9.3°C5.4°C5.4°C9016.68.58 h
December 7.4°C3.4°C3.4°C9015.87.37 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

May in nearby cities

Distance from Derry

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Derry) is explained once on the Derry year overview and on the Sources, method and limits page.