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 2025-03-12.

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	16% 12% 4 10% 5% 5% 4 3 5% 6% 29%	108883
	Night	16% 12% 5% 11% 5% 4 4 3 4 6% 29%	110085
Transparency	Day	54% 6% 11% 19% 10% 1	112524
	Night	55% 6% 11% 18% 10% 1	114584
Seeing	Day	25% 16% 28% 19% 10% 3	15052
	Night	23% 14% 27% 25% 10% 1	24744

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	14% 20% 10% 27% 6% 4 3 1 3 2 11%	3763
	11th to 20th	Day	11% 19% 11% 23% 10% 7% 2 1 2 2 11%	4060
	21st to end	Day	21% 16% 9% 14% 7% 4 4 3 4 4 16%	4466
February	1st to 10th	Day	18% 20% 6% 12% 9% 5% 4 2 3 5% 18%	1800
	11th to 20th	Day	16% 14% 7% 15% 8% 6% 4 3 4 5% 18%	1753
	21st to end	Day	20% 17% 4 12% 5% 4 4 3 5% 5% 21%	1624
March	1st to 10th	Day	20% 12% 5% 8% 5% 4 4 3 4 7% 29%	3545
	11th to 20th	Day	12% 16% 7% 10% 5% 5% 3 3 4 5% 30%	3491
	21st to end	Day	17% 11% 3 9% 6% 5% 4 4 5% 6% 31%	3815
April	1st to 10th	Day	16% 16% 3 7% 5% 4 4 5% 5% 7% 28%	2244
	11th to 20th	Day	17% 13% 3 7% 5% 4 4 3 5% 6% 33%	2254
	21st to end	Day	21% 12% 3 7% 5% 4 3 3 6% 6% 31%	2437
May	1st to 10th	Day	25% 10% 3 7% 5% 4 4 4 6% 6% 27%	4082
	11th to 20th	Day	21% 10% 3 7% 5% 5% 5% 4 6% 7% 27%	4203
	21st to end	Day	14% 7% 2 6% 4 5% 5% 4 6% 8% 39%	4823
June	1st to 10th	Day	16% 7% 3 7% 5% 5% 6% 4 7% 7% 32%	2660
	11th to 20th	Day	15% 8% 3 7% 5% 5% 5% 4 7% 9% 34%	2660
	21st to end	Day	15% 6% 2 6% 5% 5% 6% 4 6% 10% 35%	2660
July	1st to 10th	Day	10% 7% 2 7% 5% 6% 6% 5% 6% 9% 37%	4440
	11th to 20th	Day	11% 6% 3 6% 5% 6% 6% 4 7% 9% 37%	4232
	21st to end	Day	11% 8% 3 8% 6% 6% 5% 4 6% 7% 37%	4466
August	1st to 10th	Day	17% 10% 4 8% 6% 6% 5% 4 6% 7% 27%	4104
	11th to 20th	Day	13% 8% 3 8% 5% 6% 7% 4 7% 8% 33%	4044
	21st to end	Day	11% 6% 2 7% 5% 5% 5% 5% 8% 10% 37%	4229
September	1st to 10th	Day	17% 7% 3 6% 4 4 3 3 5% 6% 43%	2280
	11th to 20th	Day	13% 7% 2 6% 4 4 4 3 7% 8% 42%	2183
	21st to end	Day	21% 9% 3 6% 4 3 4 3 5% 7% 33%	2038
October	1st to 10th	Day	18% 8% 3 6% 5% 4 4 3 6% 7% 35%	1900
	11th to 20th	Day	21% 10% 3 7% 4 5% 3 4 5% 5% 33%	1900
	21st to end	Day	24% 12% 3 7% 4 4 5% 3 4 5% 31%	2090
November	1st to 10th	Day	12% 10% 3 7% 5% 5% 3 3 6% 7% 39%	1887
	11th to 20th	Day	17% 16% 4 8% 5% 4 4 3 5% 5% 28%	1600
	21st to end	Day	20% 19% 6% 8% 5% 4 3 3 5% 6% 21%	1600
December	1st to 10th	Day	18% 18% 8% 25% 5% 3 3 2 3 3 12%	2600
	11th to 20th	Day	20% 20% 7% 11% 4 3 3 2 3 4 21%	2990
	21st to end	Day	23% 25% 6% 10% 4 4 4 3 4 4 14%	3960
January	1st to 10th	Night	13% 18% 8% 25% 8% 4 3 2 3 3 12%	6165
	11th to 20th	Night	13% 16% 8% 22% 10% 6% 4 3 3 3 12%	5900
	21st to end	Night	19% 15% 8% 15% 6% 5% 5% 3 4 4 16%	6490
February	1st to 10th	Night	18% 15% 6% 13% 7% 6% 4 3 3 4 21%	2600
	11th to 20th	Night	17% 14% 5% 13% 6% 5% 5% 3 4 5% 21%	2533
	21st to end	Night	20% 13% 4 12% 5% 5% 5% 4 4 4 24%	2000
March	1st to 10th	Night	22% 12% 4 7% 5% 4 4 3 4 6% 30%	3528
	11th to 20th	Night	15% 14% 9% 8% 5% 3 3 3 4 6% 30%	3498
	21st to end	Night	16% 11% 3 7% 4 4 4 3 4 6% 38%	3817
April	1st to 10th	Night	17% 15% 5% 7% 5% 4 4 3 4 6% 30%	1934
	11th to 20th	Night	16% 11% 3 7% 4 4 5% 3 4 6% 37%	1875
	21st to end	Night	15% 11% 2 8% 6% 4 4 3 5% 6% 35%	1759
May	1st to 10th	Night	28% 10% 2 6% 4 3 4 4 4 6% 28%	2813
	11th to 20th	Night	20% 11% 3 8% 4 4 4 3 5% 6% 32%	2687
	21st to end	Night	13% 8% 3 5% 4 4 5% 4 7% 10% 37%	2732
June	1st to 10th	Night	10% 7% 2 7% 5% 5% 3 4 5% 9% 43%	1520
	11th to 20th	Night	12% 6% 2 7% 6% 5% 5% 4 7% 8% 39%	1520
	21st to end	Night	13% 6% 3 5% 4 5% 4 4 7% 9% 40%	1520
July	1st to 10th	Night	13% 8% 3 7% 5% 4 5% 4 5% 7% 39%	2520
	11th to 20th	Night	11% 6% 2 7% 5% 5% 5% 4 7% 8% 41%	2710
	21st to end	Night	12% 8% 3 8% 5% 5% 5% 3 6% 7% 40%	3087
August	1st to 10th	Night	16% 10% 3 6% 4 5% 5% 4 6% 7% 34%	2825
	11th to 20th	Night	16% 7% 2 7% 4 4 5% 4 5% 8% 39%	2785
	21st to end	Night	9% 5% 2 6% 4 5% 5% 4 6% 9% 45%	3380
September	1st to 10th	Night	14% 7% 2 4 3 3 5% 4 5% 6% 47%	1900
	11th to 20th	Night	11% 5% 2 5% 3 4 4 3 5% 8% 51%	1993
	21st to end	Night	18% 8% 3 7% 4 4 4 3 4 7% 37%	2142
October	1st to 10th	Night	17% 6% 3 6% 4 4 3 3 5% 7% 41%	2280
	11th to 20th	Night	19% 9% 2 7% 5% 4 4 3 5% 5% 37%	2280
	21st to end	Night	23% 11% 3 6% 5% 4 4 4 5% 5% 32%	2508
November	1st to 10th	Night	12% 11% 3 5% 5% 3 4 4 4 6% 43%	2403
	11th to 20th	Night	18% 15% 4 7% 5% 5% 5% 4 5% 6% 27%	2800
	21st to end	Night	19% 15% 5% 9% 5% 4 4 3 5% 5% 26%	2800
December	1st to 10th	Night	17% 16% 10% 19% 5% 4 3 3 4 5% 14%	4580
	11th to 20th	Night	22% 15% 7% 12% 5% 4 3 3 3 4 21%	5205
	21st to end	Night	18% 20% 7% 12% 6% 4 4 3 4 4 17%	6996

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	80% 3 6% 8% 3	3764
	11th to 20th	Day	82% 3 5% 7% 2 1	4060
	21st to end	Day	73% 4 8% 10% 5%	4466
February	1st to 10th	Day	72% 4 8% 11% 5%	1800
	11th to 20th	Day	68% 5% 9% 12% 5%	1762
	21st to end	Day	65% 4 11% 13% 6% 1	1624
March	1st to 10th	Day	54% 6% 11% 23% 5%	3545
	11th to 20th	Day	55% 7% 15% 17% 5% 1	3491
	21st to end	Day	51% 7% 11% 19% 11% 1	3815
April	1st to 10th	Day	54% 7% 10% 16% 11% 2	2244
	11th to 20th	Day	51% 5% 11% 16% 14% 2	2254
	21st to end	Day	52% 6% 9% 20% 12% 1	2437
May	1st to 10th	Day	55% 7% 9% 20% 7% 1	4120
	11th to 20th	Day	55% 7% 12% 17% 8% 1	4207
	21st to end	Day	39% 9% 14% 23% 12% 2	4837
June	1st to 10th	Day	47% 9% 12% 21% 11% 1	2660
	11th to 20th	Day	46% 8% 14% 20% 12% 1	2660
	21st to end	Day	44% 7% 12% 25% 12%	2660
July	1st to 10th	Day	42% 8% 12% 24% 13% 2	4370
	11th to 20th	Day	40% 8% 13% 25% 13%	4159
	21st to end	Day	43% 7% 11% 21% 17% 1	4324
August	1st to 10th	Day	53% 8% 13% 19% 7%	4091
	11th to 20th	Day	44% 8% 13% 26% 8% 1	4083
	21st to end	Day	38% 8% 14% 26% 12% 1	4229
September	1st to 10th	Day	43% 6% 9% 23% 17% 3	2280
	11th to 20th	Day	38% 7% 12% 25% 16% 1	2183
	21st to end	Day	49% 6% 12% 20% 13% 1	2038
October	1st to 10th	Day	39% 6% 11% 26% 17% 1	3160
	11th to 20th	Day	45% 6% 11% 20% 13% 4	3140
	21st to end	Day	42% 4 11% 28% 15% 1	3428
November	1st to 10th	Day	43% 7% 12% 20% 16% 2	1887
	11th to 20th	Day	57% 5% 10% 17% 9% 2	1600
	21st to end	Day	64% 5% 11% 14% 6% 1	1600
December	1st to 10th	Day	79% 4 8% 7% 2	2600
	11th to 20th	Day	68% 4 10% 15% 3	2986
	21st to end	Day	74% 4 8% 10% 4	3960
January	1st to 10th	Night	77% 4 6% 9% 3	6165
	11th to 20th	Night	78% 4 8% 7% 2 1	5900
	21st to end	Night	72% 4 9% 10% 4 1	6490
February	1st to 10th	Night	68% 4 8% 14% 6%	2600
	11th to 20th	Night	66% 4 9% 15% 6%	2535
	21st to end	Night	62% 6% 8% 15% 9% 1	2000
March	1st to 10th	Night	55% 5% 10% 23% 7%	3528
	11th to 20th	Night	54% 7% 13% 19% 6% 1	3498
	21st to end	Night	45% 6% 10% 22% 15% 2	3817
April	1st to 10th	Night	55% 5% 10% 17% 13% 1	1934
	11th to 20th	Night	48% 6% 12% 19% 14% 3	1875
	21st to end	Night	48% 6% 9% 22% 12% 2	1759
May	1st to 10th	Night	55% 7% 9% 17% 11% 2	2840
	11th to 20th	Night	51% 9% 11% 20% 8% 1	2688
	21st to end	Night	37% 11% 14% 22% 12% 4	2739
June	1st to 10th	Night	37% 8% 14% 26% 13% 2	1520
	11th to 20th	Night	40% 8% 13% 24% 13% 2	1520
	21st to end	Night	39% 9% 13% 24% 14% 1	1520
July	1st to 10th	Night	44% 7% 11% 20% 17% 2	2480
	11th to 20th	Night	37% 8% 16% 23% 15% 1	2661
	21st to end	Night	42% 7% 11% 18% 20% 2	2988
August	1st to 10th	Night	47% 8% 14% 22% 9%	2814
	11th to 20th	Night	42% 6% 13% 28% 10% 1	2812
	21st to end	Night	34% 8% 14% 31% 12% 2	3380
September	1st to 10th	Night	37% 7% 12% 24% 18% 3	1900
	11th to 20th	Night	31% 6% 12% 28% 21% 1	1993
	21st to end	Night	47% 5% 11% 20% 15% 1	2142
October	1st to 10th	Night	39% 5% 9% 25% 21% 1	3800
	11th to 20th	Night	39% 6% 12% 21% 15% 7%	3779
	21st to end	Night	40% 4 12% 25% 19% 1	4120
November	1st to 10th	Night	42% 6% 12% 21% 17% 3	2403
	11th to 20th	Night	57% 5% 10% 17% 9% 3	2800
	21st to end	Night	60% 6% 10% 18% 6% 1	2800
December	1st to 10th	Night	72% 6% 11% 8% 2	4580
	11th to 20th	Night	68% 4 11% 14% 3	5208
	21st to end	Night	69% 5% 9% 12% 4	6996

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% 28% 23% 9% 4	237
	11th to 20th	Day	36% 31% 25% 6% 2	300
	21st to end	Day	31% 25% 32% 9% 2	330
February	1st to 10th	Day	33% 27% 31% 6% 2	300
	11th to 20th	Day	40% 27% 28% 6%	300
	21st to end	Day	37% 26% 29% 8% 1	333
March	1st to 10th	Day	31% 24% 29% 13% 3	500
	11th to 20th	Day	33% 20% 31% 11% 4 1	464
	21st to end	Day	34% 22% 24% 14% 4 1	506
April	1st to 10th	Day	29% 23% 27% 16% 4 1	460
	11th to 20th	Day	27% 22% 27% 13% 7% 3	452
	21st to end	Day	30% 19% 30% 15% 5% 1	460
May	1st to 10th	Day	30% 17% 27% 16% 7% 2	463
	11th to 20th	Day	25% 14% 32% 17% 9% 3	487
	21st to end	Day	18% 11% 26% 26% 15% 5%	529
June	1st to 10th	Day	18% 17% 27% 25% 11% 2	490
	11th to 20th	Day	19% 12% 27% 24% 14% 4	490
	21st to end	Day	19% 13% 31% 23% 11% 2	490
July	1st to 10th	Day	15% 8% 25% 24% 17% 10%	485
	11th to 20th	Day	13% 8% 27% 31% 15% 7%	484
	21st to end	Day	14% 7% 30% 28% 15% 6%	532
August	1st to 10th	Day	14% 7% 22% 31% 18% 8%	486
	11th to 20th	Day	15% 7% 26% 26% 16% 10%	479
	21st to end	Day	14% 9% 25% 26% 17% 9%	539
September	1st to 10th	Day	18% 7% 24% 25% 17% 9%	490
	11th to 20th	Day	12% 6% 22% 31% 21% 8%	490
	21st to end	Day	26% 13% 24% 19% 12% 5%	490
October	1st to 10th	Day	21% 13% 23% 22% 15% 5%	490
	11th to 20th	Day	25% 16% 31% 19% 9% 2	490
	21st to end	Day	31% 17% 29% 17% 6%	539
November	1st to 10th	Day	21% 17% 30% 19% 12% 1	447
	11th to 20th	Day	29% 22% 34% 12% 3 1	200
	21st to end	Day	30% 23% 38% 9% 1	200
December	1st to 10th	Day	36% 26% 28% 8% 2 1	200
	11th to 20th	Day	39% 19% 34% 6% 3	200
	21st to end	Day	41% 20% 27% 8% 3	220
January	1st to 10th	Night	29% 23% 33% 11% 3	800
	11th to 20th	Night	32% 23% 29% 14% 2	800
	21st to end	Night	28% 23% 31% 15% 2	880
February	1st to 10th	Night	31% 20% 29% 19% 1	800
	11th to 20th	Night	32% 22% 33% 11% 1	783
	21st to end	Night	30% 23% 30% 16% 2	660
March	1st to 10th	Night	27% 20% 32% 18% 3	800
	11th to 20th	Night	29% 20% 26% 19% 6% 1	767
	21st to end	Night	25% 16% 36% 18% 5% 1	836
April	1st to 10th	Night	26% 18% 30% 21% 5%	760
	11th to 20th	Night	23% 17% 30% 21% 8% 1	751
	21st to end	Night	21% 13% 34% 27% 5%	619
May	1st to 10th	Night	23% 12% 26% 30% 8% 1	570
	11th to 20th	Night	22% 10% 29% 30% 10%	488
	21st to end	Night	12% 6% 27% 31% 22% 1	411
June	1st to 10th	Night	14% 4 28% 40% 13% 1	380
	11th to 20th	Night	13% 6% 24% 41% 14%	380
	21st to end	Night	12% 5% 30% 41% 13% 1	380
July	1st to 10th	Night	14% 4 19% 42% 18% 3	370
	11th to 20th	Night	12% 4 19% 39% 23% 3	479
	21st to end	Night	14% 3 18% 42% 22% 1	624
August	1st to 10th	Night	13% 2 18% 42% 23% 2	567
	11th to 20th	Night	15% 5% 15% 36% 26% 3	564
	21st to end	Night	12% 4 19% 37% 24% 4	779
September	1st to 10th	Night	17% 6% 19% 32% 22% 3	760
	11th to 20th	Night	13% 5% 18% 34% 26% 4	760
	21st to end	Night	21% 10% 22% 27% 16% 4	760
October	1st to 10th	Night	19% 9% 22% 29% 18% 2	760
	11th to 20th	Night	24% 13% 28% 25% 8% 1	760
	21st to end	Night	29% 14% 28% 24% 5%	836
November	1st to 10th	Night	20% 13% 30% 28% 9%	780
	11th to 20th	Night	30% 15% 28% 21% 6% 1	800
	21st to end	Night	28% 19% 30% 18% 5%	800
December	1st to 10th	Night	33% 21% 28% 14% 4	800
	11th to 20th	Night	30% 24% 26% 16% 4	800
	21st to end	Night	30% 22% 27% 19% 2	880

Page generated at 2025-03-09 08:08:47. Version ac07

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