Cooling Trend Begins as Pasadena Heads Towards Possible Weekend Rain

A cooling trend will begin Wednesday in Pasadena, with temperatures dropping back to near-normal levels by Thursday, according to National Weather Service forecasters.

The cooling marks a departure from recent warmer conditions, with high temperatures expected to reach the low 70s Wednesday under partly cloudy skies. Morning marine layer clouds may be slow to clear in some areas, and afternoon southwest winds could gust up to 15-20 mph.

Over the next 24-48 hours, temperatures will continue to cool as a trough of low pressure moves southward. Thursday will see high temperatures around 70 degrees, with similar conditions on Friday.

“The temperature trend shows a marked cooling pattern through Friday, with readings dropping from today’s low 70s to the 60s for many areas by the weekend,” the NWS reported in its forecast discussion. “This shift represents a return to seasonal norms after the recent warmer weather.”

The cooling is attributed to a strong low pressure system off the Pacific Northwest coast creating broad troughing over Southern California.

While much of the forecast period remains dry for the Pasadena area, increasing rain chances are expected by Sunday through Tuesday. Current models suggest light precipitation, generally under 0.25 inches.

Wind conditions will be relatively moderate but noticeable, particularly Wednesday afternoon. Southwest winds around 10-15 mph with occasional gusts up to 20 mph can be expected, especially in higher terrain and open areas. These breezy conditions will result from strong onshore pressure gradients that will peak on Wednesday afternoon.

Weekend temperatures will remain cool with highs in the 60s on Saturday. Sunday may be slightly cooler along the coast and valleys due to increased onshore flow as the weather pattern shifts to a more zonal upper-level flow.

For Pasadena specifically, cooler mornings with potential fog and low clouds are expected, especially in foothill neighborhoods. The cooling trend will be particularly noticeable for those who have been enjoying outdoor activities during the recent warm spell.

No weather advisories are currently in effect for the Pasadena area, though forecasts should be monitored as the weekend approaches for updated information on the potential rain system.

Looking ahead to next week, temperatures are expected to trend slightly upward by a couple of degrees on Monday and Tuesday while maintaining below-average readings. NWS forecasters indicate a more significant rain event may be possible by next Thursday or Friday (April 3-4), though this remains outside the current forecast period.

Here is the latest forecast for Pasadena from the National Weather Service as of 3:40 a.m. on Wednesday, March 27:

Wednesday: Patchy fog before 11:00 a.m. Cloudy through mid morning, then gradual clearing, with a high near 73. South southwest wind 5 to 10 mph.

Wednesday Night: Patchy fog. Otherwise, cloudy, with a low around 54. South wind around 5 mph becoming calm in the evening.

Thursday: Patchy fog before 11:00 a.m. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 69. Light and variable wind becoming southwest 5 to 10 mph in the afternoon.

Thursday Night: Patchy fog. Otherwise, mostly cloudy, with a low around 49. Southwest wind around 5 mph becoming calm after midnight.

Friday: Patchy fog before 11:00 a.m. Otherwise, partly sunny, with a high near 68.

Friday Night: Patchy fog after 11:00 p.m. Otherwise, mostly cloudy, with a low around 48.

Saturday: Patchy fog before 11:00 a.m. Otherwise, mostly sunny, with a high near 70.

Saturday Night: Patchy fog after 11:00 p.m. Otherwise, mostly cloudy, with a low around 48.

Sunday: Patchy fog before 11:00 a.m. Otherwise, partly sunny, with a high near 69.

Sunday Night: Patchy fog. Otherwise, mostly cloudy, with a low around 51.

Monday: Patchy fog. Otherwise, partly sunny, with a high near 71.

Monday Night: Patchy fog. Otherwise, mostly cloudy, with a low around 50.

Tuesday: Patchy fog. Otherwise, partly sunny, with a high near 73.