A system for detecting ice formation on aircrafts comprising: an electromagnetic resonator operating at microwave frequencies; and a data processing unit with non-transitory software implementing an algorithm to detect at least one of the presence of ice, ice type and ice thickness and output at least one of a warning and an alert, the algorithm including: a) measuring resonance frequencies ( f i) and associated quality factors ( Q d) using distribution of power of a transmitted signal (S 21) of said electromagnetic resonator; b) determining power of a transmitted signal associated with said reasonance frequencies; c) using analytical expressions or lookup tables to determine a real part of a complex dielectric permittivity (ε') at each of said resonance frequencies based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); d) using analytical expressions or lookup tables to determine an imaginary part of said complex dielectric permittivity (ε") at each of said resonance frequencies and a thickness of a layer of water or ice based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); and e) using analytical expressions or lookup tables to refine the calculations and confirm or refute the presence of water or ice. an electromagnetic resonator operating at microwave frequencies; and a data processing unit with non-transitory software implementing an algorithm to detect at least one of the presence of ice, ice type and ice thickness and output at least one of a warning and an alert, the algorithm including: a) measuring resonance frequencies ( f i) and associated quality factors ( Q d) using distribution of power of a transmitted signal (S 21) of said electromagnetic resonator; b) determining power of a transmitted signal associated with said reasonance frequencies; c) using analytical expressions or lookup tables to determine a real part of a complex dielectric permittivity (ε') at each of said resonance frequencies based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); d) using analytical expressions or lookup tables to determine an imaginary part of said complex dielectric permittivity (ε") at each of said resonance frequencies and a thickness of a layer of water or ice based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); and e) using analytical expressions or lookup tables to refine the calculations and confirm or refute the presence of water or ice. a) measuring resonance frequencies ( f i) and associated quality factors ( Q d) using distribution of power of a transmitted signal (S 21) of said electromagnetic resonator; b) determining power of a transmitted signal associated with said reasonance frequencies; c) using analytical expressions or lookup tables to determine a real part of a complex dielectric permittivity (ε') at each of said resonance frequencies based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); d) using analytical expressions or lookup tables to determine an imaginary part of said complex dielectric permittivity (ε") at each of said resonance frequencies and a thickness of a layer of water or ice based on said resonance frequencies ( f i), associated quality factors ( Q d), and distribution of power of said transmitted signal (S 21); and e) using analytical expressions or lookup tables to refine the calculations and confirm or refute the presence of water or ice.