Cleadon has quite a dry climate due to being in the lee of the Pennines and thus sheltered from the prevailing westerly winds. Rain falls frequently but is rarely heavy. It tends to be quite cool all year around, especially in summer due to the North Sea coastal influences.
Average maximum temperatures range from 7C in the winter months to 19C in July and August, so the annual range is not particularly large. Extremes of heat in summer are rare due to the tempering effects of the North Sea and I am yet to record a value of 30C or above. Values of 25C and above are possible when there is an offshore wind, clear skies and a warm airmass, but some years fail to reach 25C even once. The remarkable July of 2006 featured this setup frequently resulting in an average maximum of 23C. The North Sea is similarly effective at curbing extremes of winter cold, although on clear nights with a snow cover and a light offshore wind temperatures sometimes fall below -5C, including recordings below -10C on the 3rd March 2001 and the 3rd December 2010.
In contrast extremes of cold in summer and of heat in winter are not too unusual. On cold cloudy wet days with a strong wind vectored from the north-eastern quarter of the compass, highs of 10-12C are not unusual even in high summer, while warm winter days with a south-westerly can see a fohn effect bring maximum temperatures as high as 17C, as happened on the 13th February 1998.
Coastal Tyne and Wear ranks among the UKs sunniest regions during the winter months, as it is well sheltered from Atlantic influences by the Pennines, and some of the cloud that gets over the Pennines often burns off as it heads towards the coast. Conversely, it tends to be relatively cloudy during spring and summer, as convection, assisted by solar energy, often results in cumulus spreading into stratocumulus under an inversion, and low cloud off the North Sea is a common issue. However, it is still statistically sunnier than further inland due to those days when sea breezes keep the coast clear while cloud bubbles up inland (though you do have to take the chill of the wind off the North Sea into account then). Annual sunshine probably averaged about 1450 hours during the second half of the twentieth century but, according to the Met Offices actual and anomaly maps, most recent years have had well over 1500 hours. (Note that such totals were traditionally measured by Campbell-Stokes sunshine recorders, and that the real totals were probably a couple of hundred hours lower, as illustrated by modern Kipp & Zonen sensors, but that goes for all of the UK).
Most rainfall in Cleadon tends to be light and persistent, and Atlantic weather systems usually lose a lot of their potency by the time they get to this side of the Pennines. On occasion, though, fronts may stall over the region (usually straddling the north of England from west to east) giving large amounts of rain, usually associated with southerly tracking lows.
Convective sunshine-and-showers weather is relatively rare in Cleadon because being in the lee of the Pennines inhibits shower activity in westerly regimes, especially in winter, while in the summer the North Sea coastal influences often keep the coast clear (or foggy) while inland areas get sunshine and showers. However, under certain circumstances extreme instability can occur. In summer, this usually results from slack low pressure regimes with a light offshore wind, encouraging convective towers to sprout up over and to the east of the Pennines with convergence near the North Sea coast- a north-westerly is particularly favourable for this. In winter, a cold airflow from the north-eastern quarter of the compass, passing over the relatively warm North Sea, can give rise to heavy and occasionally thundery wintry showers.
Thunderstorms are not numerous, amounting to an average of about 8 days with thunder per year. Thunderstorm activity varies considerably from year to year- for example in 1993 there was thunder on only one day, yet July 2009 produced seven thunder-days in the space of a single month. Most thunderstorms occur during the summer months, though they are not unknown in winter either (see below).
Being in the traditionally snowy Tyne and Wear area, Cleadon gets rather more snow than most other parts of lowland England, even though it is near the coast. Cleadon tends not to get much snow from frontal events, but rather picks up a fair amount from sunshine-and-showers setups with winds from the north, northeast or east. During 1993-2008 snow became progressively less common at Cleadon, though 2009 and more especially 2010 (probably the snowiest calendar year at Cleadon since at least 1963) have bucked that trend.
In a northerly showers will often hug the east coast giving a fair amount of snow to Cleadon while further inland it stays dry. A north-easterly or easterly will often bring rain, hail and sleet showers to the coastal strip while snow falls and accumulates inland, and on rare occasions, the "snow line" can lie within the 2 mile stretch between Cleadon and the sea front.
While thunderstorms are rare during the period November-February (on average we see one every two years) all of them have resulted from this setup since I started recording, and thundersnow has occurred in 2000, 2003, 2009 and 2010. The period from 24th November-2nd December 2010 was a particularly extreme example, with sunshine and heavy snow showers and impressive cumulonimbus clouds on a daily basis, and thundersnow on two of the days.