Mobile technologies enable marketers to target consumers by time and location. This study builds on a large-scale randomized experiment of SMS sent to 12,265 mobile users. Per the contextual marketing theory, we hypothesize how different combinations of mobile targeting determine consumer responses. We identify that temporal targeting and geographical targeting individually increase sales purchases. Surprisingly, the sales effects of employing these two strategies simultaneously are not straightforward. When targeting proximal mobile users, our findings reveal a negative sales-lead time relationship; sending same-day mobile promotions yields an increase in the odds of consumer purchases by 76% compared to sending them two-day prior. However, when targeting non-proximal mobile users, there is an inverted-U, curvilinear relationship. Sending one-day prior SMSs yields an increase in the odds of consumer purchases by 9.5 times compared to same-day SMSs, and an increase in the odds of consumer purchases by 71% compared to two-day prior SMSs.