L-band (1–2 GHz) ... S-band (2–4 GHz)

The higher frequency bands typically give access to wider bandwidths, but are also more susceptible to signal degradation due to ‘rain fade’ (the absorption of radio signals by atmospheric rain, snow or ice).

If the signals are susceptible to signal degradation,  then why does gps satellites use L(L1 and L2) band for transmission? Is there any specific reason behind operating  in L band?

All GPS signals are in the L-band of the frequency spectrum ( 1–2 GHz). Because L-band waves penetrate clouds, fog, rain, storms, and vegetation, GPS units can receive accurate data in all weather conditions, day or night. There are circumstances in which GPS units may not receive signals accurately, such as inside concrete buildings or under heavy forest canopies.

The choice of the GPS carrier frequency (to transport data signals) was submitted to the following requirements:

• Frequencies should be below 2 GHz, as frequencies above 2 GHz would require beam antennae for the signal reception.

• Ionospheric delays are enormous for frequency rages below 1,000 MHz and above 10 GHz.

• The PRN codes (explained in the Glossary) require a high bandwidth for code modulation on the carrier frequency. Therefore, a range of high frequencies with the possibility of a high bandwidth had to be chosen.

• The chosen frequency should be in a range where the signal propagation is not influenced by weather phenomena like rain, snow, or clouds.

Based on these considerations, the choice of L-band frequencies proved to be advantageous. Each GPS satellite (Block IIF and beyond) transmits three carrier signals in the microwave range of the electromagnetic spectrum, designated as L1, L2, and L5 (frequencies located in the L-band between 1,000 and 2,000 MHz of the spectrum). The L1 frequency is 1,575.42 MHz (wavelength 19.05 cm), the L2 frequency is 1,227.60 MHz (wavelength 24.45 cm), and the L5 frequency is 1,176.45 MHz (wavelength 25.48 cm).

source: ascelibrary.org/doi/pdfplus/10.1061/9780784411506.ap02

Frequencies are sutficiently high (L1 = 1575.42

MHz, L2 = 1227.6M Hz) so that ionospheric absorption

and the effects of the Earth's magnetic field on

the radio signals are small (Davis and Hartmann,1997)

http://onlinelibrary.wiley.com/doi/10.1029/97RS00451/pdf

The L and S bands are used more in Mobile Satellite Services. GPS used L1. L2 L5 (L band) and IRNSS (Indian Regional Navigation Satellite System) uses both L5 and S band signals. Already the reasons have been provided, however another aspect is that using L5 and S Bands the Receiver does not need a directional antenna for the reception of the signals. On the other hand for DTH (Direct to Home) TV signals are generally at Ku or Ka Band where huge transmission rates have to be supported but they need the antennas to be pointed to the Satellites. You must have seen the satellite dish antennas pointing to the Geo Stationary Satellites from which it receives signals. For Mobile TV like (DVB-SH) lower bands are used. So in general Mobile Satellite Services used L and S Band so that the signals can be received on a Move. 

Adding to the previous answers: Satellite communications use a wide frequency spectrum, basically expanding over the whole SHF (1-40 GHz).

http://www.esa.int/spaceinimages/Images/2013/11/Satellite_frequency_bands

GPS and other positioning satellite networks reside typically in the lower range (L-/S-band) for the above mentioned reasons. Fixed Satellite Services use higher frequencies (C-/Ku-/Ka-band) to gain more bandwidth. However, recenltly also mobile satellite applications (also known as SatCom On-The-Move SOTM) are using GEO satellites in the high Ku-/Ka- bands.

https://www.researchgate.net/publication/259573213_On-Earth_Performance_Evaluation_of_SatCom_On-the-Move_SOTM_Terminals

Conference Paper On-Earth Performance Evaluation of SatCom On-the-Move (SOTM) Terminals

As L and S bands have low frequency ranges they can be used for long distance communications ,,,,this is how exactly AM RADIO works,,,LOW FREQUENCY RANGE will have long long WAVEEEEE''' LENGTHHHHH'''.....