Overall
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. Sunshine wise, Cleadon gets sunnier winters than most other parts of Britain, but summers often tend to be cloudier than in most other parts of the country.
Temperatures
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 many 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 on recording below -10C on the 3rd March 2001.
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.
Rainfall
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- 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 wintry showers.
Thunderstorms are not numerous, amounting to an average of about 7 days with thunder per year. Thunderstorm activity varies considerably from year to year- for example in 1993 there was thunder on only two days, 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).
Snowfall
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. Like other parts of the country, though, snow is less common in Cleadon than it used to be in the past.
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 I have observed "thundersnow" twice, and seen several occurrences of sleet accompanied by thunder and lightning. The convective storms from November northerlies can be especially dramatic.