Waltham weather forecast, July 30–Aug. 8, 2026

A slow-moving storm system will bring lingering showers through Thursday, with a few additional showers possible Friday before conditions improve for the weekend. Temperatures will warm back into the 80s Saturday and Sunday with increasing humidity. Another cold front is expected to bring showers and thunderstorms late Sunday into Sunday night, followed by mainly seasonable weather with more dry days than wet through the end of next week. Confidence decreases somewhat beyond August 6, but no prolonged period of unsettled weather is currently expected.