Circadian rhythms are an adaptation, ubiquitous throughout nature, that allows living organisms to anticipate daily environmental changes. The nematode Caenorhabditis elegans is emerging as a novel model in chronobiology due to the wide array of powerful genetic and neurobehavioral tools available. The N2 strain is widely used in the laboratory and considered as “wild type” although it is known to be domesticated. Various studies have shown that recently isolated strains of C. elegans are highly divergent at a genomic level when compared to the N2 strain, given the accumulation of numerous mutations in the latter. In this work, we use a locomotor activity recording system to perform a circadian screen of wild C. elegans isolates. Our results show that both the N2 strain and wild isolates were synchronized to a cold-warm (CW) cycle. MY23, JU1172, JU830 and DL238 tended to be truly entrained to the zeitgeber, while the other worm strains (especially the control N2 strain) showed varying degrees of masking. Indeed, ~30% of the N2 populations were entrained to CW cycles, increasing to 73%, 66%, 60% and 53% in the wild MY23, JU1172, JU830 and DL238 strains populations, respectively. All assayed strains retained circadian rhythms of ~24 h under constant conditions, except for JU1652 which had a period of ~23 h. Circadian characterization of wild C. elegans isolates, together with genomic data, would make it possible to identify genomic regions involved in synchronization.