Punxsutawney
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Punxsutawney clear sky chart from 2005-11-06 to 2024-02-10.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	18% 11% 5% 8% 6% 3 5% 4 5% 6% 28%	78310
	Night	17% 12% 5% 8% 6% 3 4 4 5% 6% 30%	80643
Transparency	Day	55% 6% 11% 17% 9% 1	78022
	Night	55% 6% 11% 18% 10% 1	80451
Seeing	Day	24% 16% 28% 19% 10% 4	13651
	Night	23% 14% 27% 25% 10% 1	23342

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 20% 13% 15% 6% 2 3 2 3 3 16%	2627
	11th to 20th	Day	11% 19% 11% 18% 11% 4 3 2 3 3 15%	2840
	21st to end	Day	26% 17% 10% 14% 8% 3 2 3 3 3 10%	3124
February	1st to 10th	Day	18% 19% 7% 10% 9% 5% 4 3 3 4 18%	1701
	11th to 20th	Day	17% 13% 8% 14% 8% 4 4 4 4 5% 18%	1573
	21st to end	Day	20% 15% 6% 11% 6% 4 4 3 4 5% 21%	1456
March	1st to 10th	Day	16% 12% 7% 9% 6% 3 4 4 4 7% 28%	1980
	11th to 20th	Day	18% 16% 5% 8% 5% 3 4 4 4 6% 27%	1980
	21st to end	Day	20% 12% 4 8% 6% 3 4 4 4 6% 28%	2178
April	1st to 10th	Day	16% 14% 5% 6% 5% 3 4 5% 5% 7% 29%	2125
	11th to 20th	Day	18% 12% 4 6% 5% 3 4 4 5% 6% 33%	2134
	21st to end	Day	22% 11% 3 6% 5% 3 4 4 5% 6% 31%	2308
May	1st to 10th	Day	19% 10% 4 7% 5% 3 4 5% 7% 7% 28%	2340
	11th to 20th	Day	23% 8% 4 6% 5% 4 5% 5% 6% 7% 29%	2367
	21st to end	Day	14% 7% 2 5% 5% 3 6% 5% 7% 8% 37%	2725
June	1st to 10th	Day	17% 6% 3 7% 6% 4 6% 5% 7% 7% 33%	2520
	11th to 20th	Day	16% 8% 3 6% 6% 4 6% 5% 6% 9% 33%	2520
	21st to end	Day	15% 6% 2 6% 6% 4 6% 5% 6% 10% 35%	2520
July	1st to 10th	Day	13% 7% 3 6% 6% 4 5% 5% 5% 8% 37%	2520
	11th to 20th	Day	13% 6% 3 5% 6% 4 6% 6% 8% 9% 34%	2410
	21st to end	Day	12% 7% 3 7% 7% 4 7% 5% 6% 8% 33%	2547
August	1st to 10th	Day	11% 7% 3 6% 8% 5% 6% 6% 8% 9% 31%	2327
	11th to 20th	Day	14% 7% 3 7% 6% 4 6% 6% 6% 8% 32%	2303
	21st to end	Day	15% 6% 2 6% 6% 3 5% 6% 6% 9% 34%	2411
September	1st to 10th	Day	18% 7% 3 6% 4 3 4 4 5% 6% 41%	2160
	11th to 20th	Day	14% 6% 3 5% 5% 3 4 4 7% 8% 41%	2069
	21st to end	Day	20% 8% 3 6% 5% 2 4 4 5% 7% 35%	1931
October	1st to 10th	Day	19% 8% 3 6% 6% 4 5% 4 5% 7% 34%	1800
	11th to 20th	Day	22% 10% 3 6% 5% 3 4 5% 5% 6% 32%	1800
	21st to end	Day	25% 11% 3 6% 5% 2 5% 4 4 5% 29%	1980
November	1st to 10th	Day	13% 9% 4 6% 6% 3 4 4 6% 7% 38%	1792
	11th to 20th	Day	18% 14% 5% 7% 6% 2 5% 4 5% 5% 29%	1520
	21st to end	Day	20% 17% 6% 6% 6% 3 4 4 5% 6% 22%	1520
December	1st to 10th	Day	20% 20% 10% 12% 6% 2 3 4 4 4 14%	1520
	11th to 20th	Day	18% 20% 8% 11% 5% 2 4 3 4 5% 19%	1910
	21st to end	Day	27% 23% 8% 9% 4 3 3 3 3 3 13%	2772
January	1st to 10th	Night	15% 21% 10% 14% 6% 3 4 4 3 4 16%	4301
	11th to 20th	Night	15% 17% 9% 15% 9% 5% 5% 4 3 3 14%	4120
	21st to end	Night	26% 16% 9% 11% 8% 3 3 3 3 4 15%	4532
February	1st to 10th	Night	18% 13% 7% 10% 9% 4 5% 3 4 4 22%	2464
	11th to 20th	Night	18% 13% 6% 12% 7% 4 6% 4 4 5% 21%	2273
	21st to end	Night	21% 12% 5% 11% 6% 4 4 5% 4 4 25%	1794
March	1st to 10th	Night	17% 9% 6% 7% 6% 3 5% 6% 5% 6% 29%	1980
	11th to 20th	Night	18% 13% 5% 6% 6% 2 4 4 4 6% 32%	1980
	21st to end	Night	17% 12% 4 7% 6% 3 4 4 4 6% 34%	2178
April	1st to 10th	Night	17% 13% 7% 6% 5% 3 4 4 4 6% 31%	1833
	11th to 20th	Night	15% 10% 3 6% 5% 3 5% 4 5% 6% 38%	1775
	21st to end	Night	15% 11% 3 6% 7% 3 5% 4 5% 6% 34%	1667
May	1st to 10th	Night	20% 8% 3 7% 5% 3 4 6% 5% 7% 33%	1620
	11th to 20th	Night	17% 8% 3 7% 5% 3 5% 4 5% 7% 36%	1523
	21st to end	Night	10% 6% 3 4 5% 3 4 6% 7% 9% 42%	1550
June	1st to 10th	Night	10% 7% 2 6% 5% 4 4 4 5% 9% 44%	1440
	11th to 20th	Night	13% 6% 2 6% 6% 4 5% 5% 6% 8% 38%	1440
	21st to end	Night	13% 6% 3 4 5% 3 4 5% 6% 10% 42%	1440
July	1st to 10th	Night	12% 6% 2 5% 5% 3 5% 5% 4 8% 46%	1440
	11th to 20th	Night	10% 5% 2 5% 5% 2 5% 5% 7% 9% 45%	1546
	21st to end	Night	11% 6% 2 5% 6% 3 5% 6% 7% 9% 40%	1771
August	1st to 10th	Night	9% 6% 2 4 5% 4 5% 5% 7% 9% 44%	1611
	11th to 20th	Night	13% 5% 2 6% 4 3 5% 4 6% 8% 43%	1598
	21st to end	Night	11% 5% 2 5% 5% 3 5% 5% 6% 9% 43%	1926
September	1st to 10th	Night	15% 6% 2 4 4 2 5% 5% 5% 6% 47%	1800
	11th to 20th	Night	11% 5% 2 4 3 3 4 4 5% 8% 50%	1888
	21st to end	Night	17% 7% 3 7% 5% 3 5% 4 4 7% 39%	2029
October	1st to 10th	Night	17% 6% 3 5% 5% 3 4 4 5% 7% 40%	2160
	11th to 20th	Night	19% 9% 2 6% 5% 3 4 4 6% 6% 36%	2160
	21st to end	Night	24% 11% 3 6% 5% 3 3 4 5% 5% 31%	2376
November	1st to 10th	Night	13% 10% 3 5% 5% 3 4 4 4 6% 43%	2279
	11th to 20th	Night	18% 14% 5% 6% 6% 3 5% 5% 5% 6% 28%	2660
	21st to end	Night	19% 14% 5% 8% 6% 3 4 5% 4 5% 26%	2660
December	1st to 10th	Night	21% 17% 9% 11% 6% 3 4 5% 4 5% 15%	2660
	11th to 20th	Night	19% 16% 7% 11% 7% 3 4 3 3 4 21%	3285
	21st to end	Night	22% 19% 8% 10% 7% 3 5% 4 4 5% 13%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	75% 3 7% 10% 4 1	2628
	11th to 20th	Day	76% 3 7% 10% 3	2840
	21st to end	Day	80% 4 6% 7% 2 1	3124
February	1st to 10th	Day	72% 3 8% 11% 6%	1701
	11th to 20th	Day	69% 5% 10% 12% 5%	1582
	21st to end	Day	65% 4 11% 12% 7% 1	1456
March	1st to 10th	Day	56% 6% 12% 19% 7%	1980
	11th to 20th	Day	59% 5% 9% 16% 8% 2	1980
	21st to end	Day	58% 5% 8% 17% 10% 2	2178
April	1st to 10th	Day	53% 7% 10% 17% 11% 2	2125
	11th to 20th	Day	52% 5% 11% 16% 14% 2	2134
	21st to end	Day	53% 6% 9% 19% 12% 1	2308
May	1st to 10th	Day	53% 7% 11% 18% 9% 2	2340
	11th to 20th	Day	54% 7% 10% 15% 12% 2	2371
	21st to end	Day	43% 9% 17% 21% 9% 2	2725
June	1st to 10th	Day	47% 8% 12% 21% 11% 1	2520
	11th to 20th	Day	47% 8% 14% 19% 12% 1	2520
	21st to end	Day	44% 7% 12% 25% 11%	2520
July	1st to 10th	Day	45% 8% 11% 21% 12% 3	2450
	11th to 20th	Day	42% 9% 13% 23% 12% 1	2337
	21st to end	Day	46% 8% 12% 20% 14% 1	2405
August	1st to 10th	Day	45% 10% 15% 23% 8%	2314
	11th to 20th	Day	46% 9% 15% 21% 9% 1	2303
	21st to end	Day	44% 8% 12% 21% 13% 3	2411
September	1st to 10th	Day	45% 7% 9% 22% 15% 3	2160
	11th to 20th	Day	39% 8% 12% 25% 15% 1	2069
	21st to end	Day	47% 6% 12% 21% 13% 1	1931
October	1st to 10th	Day	48% 7% 13% 19% 12% 1	1800
	11th to 20th	Day	53% 6% 11% 22% 9%	1800
	21st to end	Day	58% 5% 11% 16% 9% 1	1980
November	1st to 10th	Day	44% 7% 12% 19% 16% 2	1792
	11th to 20th	Day	57% 5% 10% 18% 8% 2	1520
	21st to end	Day	63% 5% 11% 15% 6% 1	1520
December	1st to 10th	Day	74% 5% 9% 9% 3	1520
	11th to 20th	Day	68% 4 10% 15% 3	1906
	21st to end	Day	77% 4 8% 9% 2	2772
January	1st to 10th	Night	72% 5% 7% 12% 3	4301
	11th to 20th	Night	74% 5% 10% 9% 2	4120
	21st to end	Night	75% 4 7% 10% 3 1	4532
February	1st to 10th	Night	67% 4 9% 14% 6%	2464
	11th to 20th	Night	66% 4 9% 14% 7%	2275
	21st to end	Night	63% 5% 8% 15% 9% 1	1794
March	1st to 10th	Night	53% 6% 9% 20% 11%	1980
	11th to 20th	Night	53% 6% 12% 19% 10% 1	1980
	21st to end	Night	52% 5% 8% 18% 14% 3	2178
April	1st to 10th	Night	54% 5% 10% 18% 13% 1	1833
	11th to 20th	Night	47% 6% 11% 19% 14% 3	1775
	21st to end	Night	49% 6% 10% 21% 12% 3	1667
May	1st to 10th	Night	49% 7% 10% 17% 13% 3	1620
	11th to 20th	Night	47% 8% 10% 19% 13% 2	1524
	21st to end	Night	35% 10% 16% 23% 14% 2	1551
June	1st to 10th	Night	37% 8% 14% 26% 13% 2	1440
	11th to 20th	Night	42% 8% 12% 23% 13% 2	1440
	21st to end	Night	38% 9% 14% 25% 15% 1	1440
July	1st to 10th	Night	38% 9% 12% 21% 17% 3	1400
	11th to 20th	Night	33% 7% 14% 25% 18% 2	1497
	21st to end	Night	38% 9% 14% 21% 15% 2	1672
August	1st to 10th	Night	35% 8% 16% 27% 13% 1	1600
	11th to 20th	Night	38% 7% 15% 25% 13% 2	1598
	21st to end	Night	36% 9% 14% 24% 14% 3	1926
September	1st to 10th	Night	37% 7% 12% 24% 17% 3	1800
	11th to 20th	Night	32% 7% 13% 28% 20% 1	1888
	21st to end	Night	45% 5% 12% 21% 16% 1	2029
October	1st to 10th	Night	42% 7% 13% 23% 14% 2	2160
	11th to 20th	Night	47% 5% 13% 22% 11% 1	2160
	21st to end	Night	55% 5% 10% 19% 10% 1	2376
November	1st to 10th	Night	42% 6% 12% 20% 16% 3	2279
	11th to 20th	Night	56% 5% 10% 17% 9% 2	2660
	21st to end	Night	59% 6% 10% 18% 6% 1	2660
December	1st to 10th	Night	71% 6% 9% 10% 4	2660
	11th to 20th	Night	68% 4 10% 14% 4	3288
	21st to end	Night	73% 6% 10% 9% 2	4884

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	35% 27% 24% 9% 4	213
	11th to 20th	Day	34% 31% 25% 7% 2	270
	21st to end	Day	32% 24% 33% 9% 2	297
February	1st to 10th	Day	31% 26% 33% 7% 2	267
	11th to 20th	Day	39% 27% 29% 5%	240
	21st to end	Day	38% 27% 26% 8%	273
March	1st to 10th	Day	31% 25% 31% 12% 2	420
	11th to 20th	Day	33% 20% 31% 11% 4 1	420
	21st to end	Day	34% 22% 24% 15% 5% 1	462
April	1st to 10th	Day	28% 24% 27% 15% 5% 1	420
	11th to 20th	Day	26% 22% 28% 13% 8% 4	412
	21st to end	Day	31% 19% 29% 14% 5% 1	420
May	1st to 10th	Day	30% 17% 28% 16% 7% 3	423
	11th to 20th	Day	26% 13% 34% 17% 8% 2	447
	21st to end	Day	18% 11% 26% 25% 15% 5%	485
June	1st to 10th	Day	17% 16% 28% 27% 10% 2	450
	11th to 20th	Day	21% 12% 27% 23% 13% 4	450
	21st to end	Day	19% 12% 31% 24% 12% 2	450
July	1st to 10th	Day	17% 7% 23% 24% 18% 11%	445
	11th to 20th	Day	13% 7% 27% 31% 15% 7%	444
	21st to end	Day	14% 7% 31% 28% 15% 6%	488
August	1st to 10th	Day	12% 6% 22% 33% 19% 8%	446
	11th to 20th	Day	16% 6% 25% 27% 17% 10%	439
	21st to end	Day	15% 8% 25% 26% 16% 9%	495
September	1st to 10th	Day	19% 7% 24% 25% 16% 9%	450
	11th to 20th	Day	13% 6% 22% 30% 20% 8%	450
	21st to end	Day	23% 13% 26% 20% 13% 5%	450
October	1st to 10th	Day	21% 13% 23% 22% 15% 5%	450
	11th to 20th	Day	26% 15% 31% 19% 8% 1	450
	21st to end	Day	33% 16% 29% 16% 6%	495
November	1st to 10th	Day	22% 16% 28% 20% 13% 1	412
	11th to 20th	Day	29% 22% 32% 13% 3 1	180
	21st to end	Day	27% 23% 40% 9% 1	180
December	1st to 10th	Day	37% 24% 27% 8% 2 1	180
	11th to 20th	Day	39% 19% 33% 6% 3	180
	21st to end	Day	41% 21% 27% 8% 3	198
January	1st to 10th	Night	29% 23% 33% 11% 3	760
	11th to 20th	Night	33% 21% 29% 15% 2	760
	21st to end	Night	28% 22% 31% 16% 2	836
February	1st to 10th	Night	30% 20% 30% 19% 1	759
	11th to 20th	Night	31% 23% 35% 11% 1	703
	21st to end	Night	32% 23% 28% 16% 2	592
March	1st to 10th	Night	26% 20% 33% 19% 2	720
	11th to 20th	Night	29% 20% 27% 18% 6% 1	720
	21st to end	Night	25% 16% 35% 19% 5% 1	792
April	1st to 10th	Night	26% 18% 30% 21% 5%	720
	11th to 20th	Night	23% 17% 31% 21% 8% 1	711
	21st to end	Night	21% 12% 35% 26% 5%	587
May	1st to 10th	Night	23% 12% 26% 30% 9% 1	540
	11th to 20th	Night	21% 10% 29% 30% 9%	462
	21st to end	Night	13% 6% 28% 30% 23% 1	389
June	1st to 10th	Night	14% 3 28% 41% 13% 1	360
	11th to 20th	Night	14% 7% 25% 39% 14%	360
	21st to end	Night	11% 4 29% 42% 13% 1	360
July	1st to 10th	Night	13% 3 20% 41% 19% 3	350
	11th to 20th	Night	12% 4 19% 38% 24% 3	453
	21st to end	Night	14% 3 18% 40% 23% 1	591
August	1st to 10th	Night	13% 2 18% 43% 23% 2	537
	11th to 20th	Night	15% 5% 14% 36% 27% 4	534
	21st to end	Night	12% 4 20% 35% 24% 4	738
September	1st to 10th	Night	17% 5% 20% 32% 23% 3	720
	11th to 20th	Night	13% 5% 19% 34% 25% 4	720
	21st to end	Night	19% 10% 23% 27% 17% 4	720
October	1st to 10th	Night	19% 9% 22% 30% 18% 2	720
	11th to 20th	Night	25% 13% 28% 25% 7% 1	720
	21st to end	Night	30% 14% 27% 24% 4	792
November	1st to 10th	Night	20% 13% 29% 28% 9%	740
	11th to 20th	Night	29% 16% 28% 21% 6% 1	760
	21st to end	Night	27% 19% 30% 19% 5%	760
December	1st to 10th	Night	33% 21% 28% 14% 4	760
	11th to 20th	Night	29% 24% 26% 16% 4	760
	21st to end	Night	31% 22% 27% 18% 2	836

Page generated at 2024-02-07 06:11:55. Version ac07

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