You can never really guarantee 100% it'll rain on a specific date in the future, but in some cities, there are some dates where it's at least a pretty decent bet -- even in states not exactly known for rain.
Washington is one of those states known for rain, and November 19 is that near-guarantee date for rain in Seattle. It has rained enough to measure at least 0.01 inches a whopping 92 times in the past 127 years on that date -- that's 72.4% of the time.
Portland, Oregon has an even better bet on December 1 at 74.1% -- 60 times in the past 81 years.
There are some decent bets in the opposite corner of the nation too. Miami has had rain 80 times in the past 126 years -- 63.5% -- on two dates in late September: the 25th and 29th.
Tampa's August 11th and 30th are the dates to avoid outdoor plans as it's had rain on 62.6% of those dates. Orlando too -- Sept. 7 has had rain 62% of the years since records began in 1892.
If you want more of a sure thing, head to Alaska
The Alaska panhandle has towns like Juneau (Oct. 13) and Ketchikan (Oct. 8), where it has rained 85% of the years on those dates.
Or if you want the SUREST WEATHER BET IN AMERICA….
Predict rain in Hilo, Hawaii on July 30. Any July 30.
In the 72 years of records there, it has rained every year on July 30.
For 70 of the years, the rain gauge had measurable rain and two years had just a trace of rain, but there was nary a dry day.
July 15 is a close second at 71 out of 72 years with rain. Only July 15, 2001, did the city not receive a single drop on that date.
Then again, Hilo is one of the wettest cities in America, averaging over 10 FEET of rain per year.
The everlasting trade winds run into the mountainous terrain there, squeezing out the tropical moisture on a near-daily occurrence.
Hilo's average driest month in May is still a half-inch wetter than Seattle's average wettest month of the year in November.
Speaking of Seattle, it did indeed rain on Friday morning!