Abstract Background Healthcare-associated infections pose a major, yet often preventable risk to patient safety. Poor hand hygiene among healthcare personnel and unsanitary hospital environments may contribute to this risk in low-income settings. We aimed to describe hand hygiene behaviour and environmental contamination by season in a rural, sub-Saharan African hospital setting. Methods We conducted a concurrent triangulation mixed-methods study combining three types of data at a hospital in Madarounfa, Niger. Hand hygiene observations among healthcare personnel during two seasons contributed quantitative data describing hand hygiene frequency and its variability in relation to seasonal changes in caseload. Semistructured interviews with healthcare personnel contributed qualitative data on knowledge, attitudes and barriers to hand hygiene. Biweekly environmental samples evaluated microbial contamination from October 2016 to December 2017. Triangulation identified convergences, complements and contradictions across results. Results Hand hygiene compliance, or the proportion of actions (handrubbing or handwashing) performed out of all actions required, was low (11% during non-peak and 36% during peak caseload seasons). Interviews with healthcare personnel suggesting good general knowledge of hand hygiene contradicted the low hand hygiene compliance. However, compliance by healthcare activity was convergent with poor knowledge of precise hand hygiene steps and the motivation to prevent personal acquisition of infection identified during interviews. Contamination of environmental samples with gram-negative bacilli was high (45%), with the highest rates of contamination observed during the peak caseload season. Conclusion Low hand hygiene compliance coupled with high contamination rates of hospital environments may increase the risk of hospital-acquired infections in sub-Saharan African settings.