If you plan to record outdoors, rest assured you'll have to deal with less than ideal weather conditions from time to time. Of particular concern are the detrimental effects of rain and snow on your precious (i.e. expensive) audio equipment. Wet weather and electronic gear mix like oil and water, so you'll do well if you prepare for the worst.
Keep your gear high and dry
Audio equipment does not like water. Don't get stuck out in the rain - If you are planning to record and there's even the slightest hint of approaching rain, zipper sandwich bags come in handy with your audio equipment. Wired microphones fare better in the elements, but it's still a good idea to keep the connectors dry with a simple wrap of electrical tape. The same applies for battery doors.
Exposed microphones - whether handheld, shotgun or lapel - are more of a sticking point. It's never a good idea to get a microphone wet, regardless of type or application. For a quick outdoor shoot, a simple foam windscreen will keep the microphone dry enough.
The elements don't have to ruin your audio | CMTO
The Windscreen is Your Friend
Whether you record in wetness or not, every outdoor recorder has to deal with wind noise. Uncontrolled, wind noise can render your audio useless and there is no way to repair the damage in post-production. Regardless of the audio you capture outside, your microphone needs a windscreen. Along with the windscreen, we put together a list of things every good audio content creator should own.
Professional microphone zeppelins or windsocks can cost several hundred dollars and aren't worth the cost for casual use. A few dollars and a trip to the fabric store will supply most of what you need to build a simple windsock. First, pick up a small roll of fiber batting - the type used to fill quilts and blankets. Next, buy some costume fur with a nap of one inch or longer. Installation is simple. First, wrap some batting around your microphone, securing it with rubber bands. Then, do the same with the fur if you're shooting in strong winds. This setup will likely thin out the sound, but wind noise won't be as much of an issue.
Minimising the effect of background location noise whilst recording
Whether outdoors means mountain streams or traffic jams, you have to deal with unwanted noises in your audio. These may manifest themselves as simple, random interruptions or as a constant roar that all but obscures the sound you want to record. In any case, there are weapons at your disposal to minimize these effects.
The simplest technique is to use natural barriers to block the noise. If you're recording using a handheld or lapel microphone, position him with his back to the noise. His body will block a great deal of noise and can make an impractical setup feasible. You can exploit other barriers such as buildings, rocks and trees to similar effect. When using a directional shotgun microphone, utilize the built-in null points to your advantage. You can leverage this knowledge of pickup patterns by placing the microphone where it will pick up the maximum amount of sound you want and a minimum of the sound you don't.
If the area you're featuring contains colorful audio, capture several minutes of sound on tape after the shoot. In the editing process, you'll have a way to cover abrupt edits and scenic shots that don't have acceptable audio. Properly blended, these patches will sound perfectly natural, plus you'll have another soundscape for your audio effects library. It is better to have the option to add ambient noise back into the mix in post than to try and remove it.
Use a pair of sealed-cup headphones. These will block outside sounds and allow you to concentrate on what's coming through the microphone. Cup headphones fair much better than earbuds especially when recording on a windy or rainy day. You can really focus on what sounds are being recorded and monitor the sound levels.