I don't know if the outside temperature has anything to do with your problem. I think it may just be
coincidental. Water accumulating in the tub is usually caused by two things:
Leak by - which is caused by a water inlet valve malfunction. The valve has an electronically controlled diaphragm that closes to shut the water off when not in use. Over time the valve can accumulate sediment and debris causing the valve not to seat all the way. This is especially true if you live in an area that has hard water, or if you use well water. This will cause water to leak by when the valve is not in use and accumulate over time in the wash tub. You can attempt to clean the valve with distilled vinegar to remove any sediments and flush it with clean water. You will need to remove the valve in order to do this. Sometimes a good cleaning is all it takes to correct the problem. If not, I would recommend replacing it.
Siphoning - siphoning occurs when the drain line is installed incorrectly. The following link explains:
http://www.fixya.com/support/r587481-prevent_washer_siphoning
Although the problem usually describes a condition where a washer
constantly fills and drains, or cannot maintain the proper water level, it can also cause back flow from the drain. Double check your drain line installation to ensure there is a proper air gap to allow for proper draining. If not, a vacuum is created and drain water can back flow into the washer.
A simple test would be to shut the water supply off when not in use. If the washer STILL accumulates water, you know you have a drain problem. If it does NOT, then you know you have an inlet valve issue.
I hope you find this information helpful. Let me know if you still require assistance.