It is more common to encounter adverse weather conditions in games than in practice.  On practice days most teams will simply go indoors or reschedule if there is light rain, the field is wet,  winds are high, temperatures are low, or if fog happens to roll in. But on game days it is more likely teams will play through worse conditions than they are willing to practice in.  

During the course of a game weather conditions can worsen to the point where it seems like you're battling them and the hitter equally. The first step is to recognize what conditions you have to deal with and then continue to adjust as the game progresses.  Another factor to take into account is that playing conditions affect everyone on the field, especially the hitter, so conditions can also play a role in your game plan.

Rain and a wet field can make pitch command much more difficult than it is in a dry bullpen.  A muddy playing surface and high humidity has a bigger effect on the pitcher than the same conditions for the hitter.  Generally hitters have less movement with their lower bodies so footing isn't as big of an issue.  Hitters also have batting gloves and pine tar to help with the grip of the bat while pitchers only have the option of a wet rosin bag and a bare throwing hand.  

Adjustments for wet conditions include

• Keep a tongue depressor on the mound to clean mud off your spikes
• Keep a mini rosin bag in your back pocket
• Aim for a bigger portion of the Go Zone early in the count
• Throw a lower percentage of breaking balls than normal
• Communicate with umpire about mound conditions 
• Ask for a new ball as often as needed 

In cold temperatures the pitcher has a slight advantage because they are in constant motion while on the mound and don't have to swing a bat that could possibly ring the hands.  Hitters are generally more vulnerable to the pitch inside on a cold day compared to a warm one.  Once you jam a hitter early in the game or see them shaking their hands after a foul ball, generally a bigger percentage of the outer part of the plate is open.  Watch the body language of the hitter to see if they are struggling with the cold.

Adjustments for cold conditions include

• Toss between all long innings on the side
• Keep a hand warmer in your back pocket
• Challenge hitters inside more often
• Get the most out of warm up pitches before the inning
• Ask umpire if you can warm hand with breath on the mound
• Keep pitch count down and work quickly

Windy conditions can give either the hitter or the pitcher a big advantage.  Obviously if the wind is blowing out the ball will go further off the bat and with the wind blowing in the ball will get knocked down.  From the mound, wind strength and direction can play a role within the game plan.  

When the wind is blowing out there will be more air resistance on the pitch as it moves to the plate, this will increase movement on all pitches.  Pitchers and catchers can adjust by accounting for extra movement when choosing pitches and Zones to aim for.  Usually more movement on the pitch allows pitchers to be more aggressive in the Go Zone.

When the wind is blowing in there will be less air resistance on the pitch, this will decrease movement on all pitches.  Pitchers and catchers can adjust by accounting for less movement when choosing pitches and Zones to aim for.  Usually less movement on the pitch makes pitchers be a little more fine with Lokations and could possibly call for more variety in pitch calling.  

Make sure to practice throwing bullpens in as many adverse weather conditions as possible.  Challenge friends and teammates to go outside and compete throwing bullpens against each other with the Lokator Bullpen App when weather is bad but playable.  Compare Lokation results in bad and good weather.  As always, make adjustments accordingly.