First 90°F or Higher Each year 1887-2025

NOTE: >> data tables are located below the graph

The new 30-year (1991-2020) NORMAL is May 8, Calendar Day of the Year 128.
The old 30-year (1981-2010) NORMAL was May 16, Calendar Day of the Year 136.
 
The 139 year (1887-2025) average is May 16, Calendar Day 136

Recent:
Year 2025: April 28, Calendar Day 118, or, 10 days earlier than normal
Year 2024: June 5, Calendar Day 157, or 29 days later than normal
Year 2023, May 7, Calendar Day 127, or, 1 day earlier than normal 
Year 2022, April 12, Calendar Day 105, or, 30 days earlier than normal
Year 2021, April 26, Calendar Day 116, or, 12 days earlier than normal
Year 2020, May 1, Calendar Day 122, or 6 days earlier than normal

Climatology of Lincoln's First  90°F or higher temperature - 
Listed yearly. Data 1887-2025

-----------------------------------------------------------------------------------------

DOTY = Day of The Year or Calendar Day.
NOTE:  LY = Leap Year. Leap Year information can be found below the next table.
For example, May 19 is Calendar day 139 in 1975 but in Year 1976, a leap year, it was day 140.

 ----------------------------------------------------------------------------------------

Day of the year (DOTY), non-leap years:

* Feb 29 exists only in a leap year.
During leap years, add 1 day to all days March 1-December 31.

Leap Year background information:
Leap years are years with 366 days, instead of the usual 365. Leap years are necessary because the actual length of a year is 365.242 days, not 365 days, as commonly stated. Basically, leap years occur every 4 years, and years that are evenly divisible by 4 (2004, for example) have 366 days. This extra day is added to the calendar on February 29th.

However, there is one exception to the leap year rule involving century years, like the year 1900. Since the year is slightly less than 365.25 days long, adding an extra day every 4 years results in about 3 extra days being added over a period of 400 years. For this reason, only 1 out of every 4 century years is considered as a leap year. Century years are only considered as leap years if they are evenly divisible by 400. Therefore, 1700, 1800, 1900 were not leap years, and 2100 will not be a leap year. But 1600 and 2000 were leap years, because those year numbers are evenly divisible by 400.