- The average ice out date is April 29th.
- The average ice-out date has varied by decades:
| 1920's |
May 2 |
| 1930's |
April 28 |
| 1940's |
April 25 |
| 1950's |
May 2 |
| 1960's |
May 2 |
| 1970's |
May 2 |
| 1980's |
April 26 |
| 1990's |
April 29 |
| 2000's |
April 26 |
- The earliest ice-out was April 6, 2010. The latest was May 23, 1950.
- The ice has never gone out on April 15th. (Too taxing!)
- The percentage (rounded) of time the ice will go out on the following dates:
(2010 data - the percentages do not change significantly year to year,
Plans are to update the percentages every 5 to 10 years.)
|
Before April 5
|
.26%
|
|
April 6
|
.12%
|
|
April 7
|
.14%
|
|
April 8
|
.21%
|
|
April 9
|
.29%
|
|
April 10
|
.34%
|
|
April 11
|
.47%
|
|
April 12
|
.61%
|
|
April 13
|
.70%
|
|
April 14
|
.95%
|
|
April 15
|
1.17%
|
|
April 16
|
1.42%
|
|
April 17
|
1.55%
|
|
April 18
|
1.97%
|
|
April 19
|
2.31%
|
|
April 20
|
2.41%
|
|
April 21
|
2.96%
|
|
April 22
|
3.31%
|
|
April 23
|
3.32%
|
|
April 24
|
3.92%
|
|
April 25
|
4.21%
|
|
April 26
|
4.05%
|
|
April 27
|
4.60%
|
|
April 28
|
4.73%
|
|
April 29
|
4.78%
|
|
April 30
|
4.56%
|
|
|
May 1
|
4.70%
|
|
May 2
|
4.56%
|
|
May 3
|
4.01%
|
|
May 4
|
4.13%
|
|
May 5
|
3.85%
|
|
May 6
|
3.25%
|
|
May 7
|
3.22%
|
|
May 8
|
2.88%
|
|
May 9
|
2.53%
|
|
May 10
|
2.02%
|
|
May 11
|
1.90%
|
|
May 12
|
1.60%
|
|
May 13
|
1.23%
|
|
May 14
|
1.11%
|
|
May 15
|
.90%
|
|
May 16
|
.67%
|
|
May 17
|
.57%
|
|
May 18
|
.45%
|
|
May 19
|
.31%
|
|
May 20
|
.26%
|
|
May 21
|
.20%
|
|
May 22
|
.14%
|
|
May 23 and after
|
.17%
|
|
- The National Climatic Data Center and international standards require
that climate "normals" (averages) be based on 30 year records. Thus,
the "normals" from 1971 to 2000 are updated for years 1981 to 2010. The
following table indicates "ice-out" trends using this standard on "ice-out"
dates:
| Years |
Ave. Ice-Out Date |
Earlier/Later* |
By Time** |
| 1923-1950 |
April 29 |
na |
na |
| 1931-1960 |
April 28 |
Earlier |
2 hr. 3 min. |
| 1941-1970 |
April 30 |
Later |
32 hr. 0 min. |
| 1951-1980 |
April 30 |
Later |
19 hr. 12 min |
| 1961-1990 |
April 29 |
Earlier |
32 hr. 0 min. |
| 1971-2000 |
April 28 |
Earlier |
27 hr. 12 min. |
| 1981-2010 |
April 27 |
Earlier |
24 hr. 15 min. |
| * Earlier or later than previous 'ice-out' period. |
| ** Earlier or later by time from previous period (these times are relative,
not absolute 'ice-out' times, and are presented for comparison purposes
only. The average 'ice-out' time for all recorded years is 0 hours, 0 min.
into the April 29th 24 hour clock. |
|
