diff --git a/src/main.cpp b/src/main.cpp
index dba5f23..eb4df8e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -182,19 +182,13 @@ int main(int argc, char *argv[]) {
 	std::cout << "Starting " << wc << " worker threads..." << std::endl;
 	for (unsigned int w = 1; w <= wc; w++) {
 		workers.push_back(std::thread([&it, &n_done, &it_lock, &all_fires,
-				&residentials, &out_dir, w, distance]() {
-			for (;;) {
-				it_lock.lock();
-				if (it == all_fires.end()) {
-					std::cout << "Worker " << w << " done! (finished " << n_done
-							<< "/" << all_fires.size() << ")" << std::endl;
-					it_lock.unlock();
-					return;
-				}
+									   &residentials, &out_dir, w, distance]() {
+			it_lock.lock();
 
+			while (it != all_fires.end()) {
 				const auto& month_data = *(it++);
-				auto& month = month_data.name;
-				auto& month_fires = month_data.days;
+				const auto& month = month_data.name;
+				const auto& month_fires = month_data.days;
 				std::cout << "Worker " << w << " processing data from " << month
 						<< "... (finished " << n_done << "/"
 						<< all_fires.size() << ")" << std::endl;
@@ -225,12 +219,13 @@ int main(int argc, char *argv[]) {
 					outf << '\n';
 				}
 
-				{
-					std::lock_guard<std::mutex> lk(it_lock);
-
-					n_done++;
-				}
+				it_lock.lock();
+				n_done++;
 			}
+
+			std::cout << "Worker " << w << " done! (finished " << n_done
+					<< "/" << all_fires.size() << ")" << std::endl;
+			it_lock.unlock();
 		}));
 	}