For now i found this solution:
I changed a pressureAvg and pressureSamples to unsigned int. Next changed int forecast = sample(pressure) to int forecast = sample(pressure * 10) to avoid big precision lost. Sample function still may need correction but probably it is a good and easy way to fix this problem.

Result:
Sketch uses 18,636 bytes (60%) of program storage space. Maximum is 30,720 bytes.
Global variables use 1,268 bytes (61%) of dynamic memory, leaving 780 bytes for local variables. Maximum is 2,048 bytes.

Hello,
I've tried to use a pressureSensor example but Arduino nano clone didn't send any data. During compilation i have seen:

Sketch uses 23,540 bytes (76%) of program storage space. Maximum is 30,720 bytes.
Global variables use 1,677 bytes (81%) of dynamic memory, leaving 371 bytes for local variables. Maximum is 2,048 bytes.
Low memory available, stability problems may occur.

Serial was looped:
send:sensor started, id 1
send:sensor started, id 1
send:sensor started, id 1
send:sensor started, id 1

I solved this problem by disable weather forecast. I suppose device run out of memory with enabled weather forecast.