Since August 2003, the MINOS Far Detector collected over 67 million underground muons at Soudan MN, USA. As the temperature of the atmosphere changes, the interaction height of incident cosmic rays changes, which affects the production of muons that are seen underground. A four percent peak-to-peak seasonal fluctuation was seen over a period of four years, which was highly correlated to the measured temperature variations of the upper atmosphere over the same period. The coefficient relating changes in the muon rate to changes changes in atmospheric temperature, α_T , was found to be: α_T = 0.877 ± 0.010 (stat.) ± 0.017 (syst.). A new model was developed to describe the observed effect, and is the first to include the contribution from kaons. This model predicts α_T = 0.865 ± 0.015. The first measurements of charge separated seasonal variations were reported: α_T(μ⁺) = 0.782 ± 0.056 (stat.) ± 0.02 (syst.), α _T(μ⁻) = 0.788 ± 0.066 (stat.) ± 0.02 (syst.). The measurable inclusion of kaons in the theoretical expression for α_T allowed a measurement of the atmospheric K/π ratio = 0.21 ± 0.08.

A high significance observation of two muon signals, the shadow of the sun and moon, have been seen. The shadow of the moon was observed at the 5 σ level, and the shadow of the sun was observed at the 4.3 σ level. The angular resolution of the detector was found to be 0.62° using dimuons, and the two dimensional shadowing distribution was used to quantify the absolute pointing of the detector 0.15 ± 0.10°.

A cosmic ray point source search was performed, and no statistically significant source was found. In the absence of a source, 95% flux limits were placed on cosmic ray sources. The minimum flux limit was 2.7 × 10⁻¹⁶ cm⁻²s⁻¹, which is comparable to the previous best limit set by MACRO [1,2]. Using the 239 Gamma Ray Bursts (GRBs) of the first Swift catalog a search for space-time coincidence between neutrino induced muons and GRBs was performed. In the absence of a statistically significant coincidence, 90% flux limits were placed on neutrino production in GRBs. Assuming a Waxman-Bahcall neutrino spectrum [3], the average 90% flux limit was found to be 1.7 × 10⁻⁸ GeV cm⁻²s⁻¹. This new limit is slightly better than the MACRO [4] and AMANDA [5] limits as well as the theoretical limit set by cosmic rays [6, 7], but does not constrain the model.