In　this　paper,　we　proposed　a　theoretical　model　to　study　the　dispersion　of　hydrogen.　The　model　given　a　correlation　between　the　concentration　and　temperature　for　cryogenic　gases.　The　model　based　on　adiabatic　mixing　hypothesis　and　neglected　exterior　heat　sources,　and　thought　the　gas　mixture　was　always　at　quasi-steady　state.　Real-gas　law　was　adopted,　and　thermal　physical　properties　of　the　gases　are　obtained　from　NIST　REFPROP　database.　The　concentration　curve　approximately　appears　a　decreasing　straight　line,　and　turns　on　dew　point　and　ice　point,　since　heat　released　from　water　vapor　phase　change.　Compared　with　liquid　hydrogen　and　liquid　natural　gas　spill　experimental　data,　the　model　obtained　well　agreement　solutions.　Effects　of　three　typical　weather　conditions　(atmospheric　temperature,　relative　humidity　and　barometric　pressure)　on　hydrogen　dispersion　were　quantitatively　studied.　It　is　confirmed　that　the　dispersion　is　excited　in　summer,　and　is　depressed　in　winter　and　transition　seasons　with　increased　ambient　temperature.　With　increased　ambient　temperature,　the　effect　of　increased　enthalpy　reduction　of　the　dry　air　components　and　the　effect　of　the　water　latent　heat　are　respectively　dominate　in　the　268.15–293.15　K　and　293.15–308.15　K　ranges.　Compared　to　ambient　temperature　and　barometric　pressure,　relative　humidity　has　the　strongest　positive　effect　on　hydrogen　dispersion,　and　the　slight　dampening　effect　of　barometric　pressure　could　be　neglected.　©　2020　Hydrogen　Energy　Publications　LLC