Bouldering and climbing are often weather dependent, so its useful to know what conditions are like in the area you are intending on heading to.
UKB Forum has the two sub-forums for conditions, one for Bouldering and one for Climbing and posts to both are automatically tweeted. Posting on one of the threads in these forums about the conditions at a particular area will often elicit a response from a local as to the current conditions in the area.
However, another useful resource is the plethora of Web-Cams that now cover the country. Whilst very few of these are actually at the crags and bouldering venues they can provide an overview of the weather in the area.
Peak District Hathersage (Outside WebCam)
Froggatt and Curbar webcam
A53 Buxton to Leek (Cat & Fiddle Pub)
A53 Winking Man pub, looking over towards Newstones
HSE site nr Harpur Hill (SK055705)
Towards Whaley Moor
Leek (near the Roaches)
Jodrell Bank (also near the Roaches)
Derbyshire Webcams A collection of many of the above on one page.
Lancashire Chipping near Longridge and Crag Stones
Hurst Green near Longridge
Garstang north of Preston
Caton near Lancaster, good for Limestone areas and Thorn Crag
Todmorden near Bridestones and nearish to Blackstone Edge and Cow's Mouth
Lake District Lake Windermere, good for Brant Fell
Little Langdale, 360 deg. views, good for Langdale and Chapel Stile (scroll down for web cam)
South end of Derwent Water, good for the Bowderstone (scroll down for web cam)
Latrigg Fell from Keswick, good for Carrock Fell
South end of Lake Ullswater, good for Rolling Rock and Dove Crag (scroll down for web cam)
North end of Lake Coniston, good for Lad Stones
Yorkshire Wetherby Race course (good for Almscliff weather)
Ilkley web cam
Swaledale web cam (Not far north of Slipstones - & high)
Beatties Deli & Coffee Shop in Holmfirth - Good indicator of local dryness
Haworth, good for Earls Crag and Widdop area
Burnsall, good for Rylstone and Simon's Seat moors
Skyreholme, looking at Simon's Seat
Todmorden near Bridestones, Mytholm Steeps and Widdop
South West Dartmoor
Webcam at Symonds Yat overlooks the car park used for Huntsham. Useful for all Forest/Wye Valley venues.
Bristol webcam (Avon area).
Cheddar, Brean, Uphill, etc.
Wales Abersoch (including Vaynol Arms)
Llandudno (Orme, Parasilla's)
Snowdonia (from Anglesey)
Snowdonia (from Bangor)
Vivian Quarry (from Llanberis)
Ogwen Mountain Rescue Team Base (Capel Curig)
Nant Peris, Porthmadog & Porth Ysgo
Llanrwst and the Carneddau
Abergavenny, close to Hatterrall hill. 30km from Dinas in one direction and Huntsham, and other wye valley venues in the other
Langland Bay, The Gower near Swansea - choose from several views
Rhossili Beach on the tip of the Gower
Newgale Beach Webcam
Llanferres, Mold (Pantymwyn) Webcam