Wawa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wawa clear sky chart from 2005-11-06 to 2024-02-05.

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% 5% 8% 6% 3 5% 5% 5% 7% 29%	77796
	Night	15% 14% 6% 9% 7% 4 5% 4 5% 6% 26%	81101
Transparency	Day	55% 7% 13% 17% 8% 1	77491
	Night	58% 7% 12% 16% 7% 1	80942
Seeing	Day	22% 15% 32% 20% 8% 2	14496
	Night	21% 12% 30% 26% 9% 1	24052

By Month

Percentage Cloud Cover NE (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	10% 24% 9% 14% 9% 4 4 5% 4 5% 12%	2280
	11th to 20th	Day	8% 16% 6% 14% 11% 3 5% 4 5% 7% 21%	2530
	21st to end	Day	8% 26% 13% 10% 7% 4 4 4 5% 5% 13%	2783
February	1st to 10th	Day	7% 14% 6% 9% 10% 6% 7% 6% 5% 6% 24%	1510
	11th to 20th	Day	9% 16% 8% 11% 8% 5% 4 4 5% 6% 24%	1645
	21st to end	Day	7% 18% 9% 12% 10% 4 7% 4 4 6% 19%	1480
March	1st to 10th	Day	10% 12% 5% 9% 7% 4 5% 5% 5% 6% 32%	1798
	11th to 20th	Day	13% 12% 4 10% 6% 3 5% 4 3 5% 34%	1939
	21st to end	Day	14% 11% 5% 8% 7% 4 6% 4 5% 7% 30%	2240
April	1st to 10th	Day	18% 13% 5% 8% 6% 4 5% 5% 5% 6% 25%	2160
	11th to 20th	Day	19% 12% 5% 8% 5% 3 5% 4 5% 5% 30%	2294
	21st to end	Day	17% 10% 4 7% 6% 2 4 4 4 6% 34%	2340
May	1st to 10th	Day	16% 8% 4 7% 6% 4 6% 5% 5% 8% 32%	2340
	11th to 20th	Day	19% 8% 3 6% 6% 3 4 4 5% 5% 37%	2514
	21st to end	Day	18% 7% 3 5% 5% 3 4 5% 5% 8% 37%	2919
June	1st to 10th	Day	18% 7% 3 6% 6% 3 6% 5% 5% 7% 33%	2700
	11th to 20th	Day	16% 8% 3 6% 5% 3 6% 5% 6% 8% 35%	2700
	21st to end	Day	20% 6% 2 6% 5% 3 4 5% 5% 8% 37%	2700
July	1st to 10th	Day	15% 6% 3 5% 4 3 5% 5% 5% 9% 41%	2700
	11th to 20th	Day	14% 6% 3 6% 5% 3 5% 6% 6% 8% 39%	2608
	21st to end	Day	16% 7% 3 5% 4 3 5% 5% 6% 8% 37%	2743
August	1st to 10th	Day	14% 7% 3 6% 6% 4 5% 5% 6% 10% 33%	2481
	11th to 20th	Day	15% 7% 3 5% 5% 3 4 4 5% 7% 42%	2303
	21st to end	Day	20% 7% 2 5% 5% 2 5% 5% 5% 8% 36%	2573
September	1st to 10th	Day	22% 6% 3 6% 4 3 4 5% 5% 7% 36%	2134
	11th to 20th	Day	23% 7% 3 5% 4 2 4 5% 5% 8% 34%	1980
	21st to end	Day	24% 9% 3 6% 5% 3 4 4 5% 8% 30%	1980
October	1st to 10th	Day	22% 12% 4 7% 5% 3 4 4 5% 6% 28%	1940
	11th to 20th	Day	24% 16% 5% 7% 7% 3 5% 4 5% 7% 18%	1675
	21st to end	Day	24% 19% 6% 8% 7% 3 5% 4 3 4 17%	1782
November	1st to 10th	Day	22% 16% 6% 7% 6% 3 5% 4 4 7% 19%	1672
	11th to 20th	Day	17% 19% 7% 10% 7% 4 3 5% 5% 5% 18%	1562
	21st to end	Day	20% 22% 8% 10% 7% 4 5% 5% 5% 5% 11%	1359
December	1st to 10th	Day	11% 19% 8% 12% 8% 4 6% 5% 6% 6% 13%	1330
	11th to 20th	Day	13% 18% 8% 11% 9% 4 5% 4 5% 7% 15%	1671
	21st to end	Day	23% 21% 7% 11% 6% 2 4 4 4 6% 11%	2431
January	1st to 10th	Night	9% 20% 11% 15% 7% 4 3 4 5% 6% 16%	4674
	11th to 20th	Night	7% 15% 7% 17% 12% 4 5% 4 5% 6% 19%	4440
	21st to end	Night	11% 21% 14% 13% 8% 4 5% 4 3 4 14%	4884
February	1st to 10th	Night	8% 14% 7% 10% 9% 6% 6% 6% 6% 7% 23%	2544
	11th to 20th	Night	10% 14% 7% 12% 8% 4 6% 6% 6% 6% 21%	2199
	21st to end	Night	9% 17% 8% 12% 8% 4 5% 4 4 6% 24%	1776
March	1st to 10th	Night	9% 11% 4 9% 7% 4 4 5% 4 8% 34%	2149
	11th to 20th	Night	13% 12% 5% 6% 6% 3 4 5% 6% 6% 34%	2020
	21st to end	Night	11% 9% 4 7% 7% 4 6% 5% 5% 5% 37%	2132
April	1st to 10th	Night	18% 12% 4 8% 6% 3 5% 5% 5% 7% 28%	1800
	11th to 20th	Night	18% 10% 4 6% 5% 3 5% 5% 5% 6% 33%	1614
	21st to end	Night	17% 10% 3 7% 5% 2 3 4 5% 6% 37%	1620
May	1st to 10th	Night	15% 8% 4 7% 7% 4 4 6% 6% 7% 33%	1617
	11th to 20th	Night	18% 8% 4 5% 5% 4 5% 4 4 6% 36%	1381
	21st to end	Night	17% 9% 3 5% 4 2 4 4 5% 6% 41%	1357
June	1st to 10th	Night	16% 7% 3 6% 5% 5% 4 5% 5% 5% 39%	1260
	11th to 20th	Night	19% 7% 3 6% 4 3 5% 4 5% 7% 37%	1260
	21st to end	Night	17% 6% 3 6% 5% 4 4 5% 5% 7% 38%	1260
July	1st to 10th	Night	11% 6% 2 6% 7% 3 4 5% 5% 10% 39%	1260
	11th to 20th	Night	14% 7% 3 6% 6% 4 5% 5% 7% 8% 35%	1349
	21st to end	Night	16% 6% 3 6% 5% 3 4 5% 6% 9% 38%	1575
August	1st to 10th	Night	13% 7% 2 6% 6% 4 4 4 5% 10% 39%	1457
	11th to 20th	Night	11% 6% 2 5% 4 3 4 5% 6% 7% 48%	1598
	21st to end	Night	18% 6% 2 5% 5% 2 4 4 4 8% 42%	1782
September	1st to 10th	Night	16% 7% 2 5% 5% 3 4 6% 5% 6% 41%	1807
	11th to 20th	Night	19% 7% 2 5% 6% 3 4 4 5% 6% 39%	1980
	21st to end	Night	24% 8% 3 4 5% 3 4 4 5% 8% 33%	1980
October	1st to 10th	Night	22% 11% 3 7% 5% 3 4 4 5% 6% 32%	2020
	11th to 20th	Night	23% 13% 3 6% 7% 3 5% 4 6% 6% 24%	2281
	21st to end	Night	22% 17% 6% 8% 7% 3 4 5% 4 5% 19%	2574
November	1st to 10th	Night	19% 14% 6% 9% 6% 4 5% 4 4 6% 24%	2406
	11th to 20th	Night	21% 15% 5% 10% 7% 4 4 4 4 5% 19%	2617
	21st to end	Night	18% 21% 7% 10% 8% 4 5% 4 3 4 15%	2816
December	1st to 10th	Night	12% 21% 7% 11% 7% 4 6% 5% 6% 5% 17%	2850
	11th to 20th	Night	13% 19% 8% 10% 7% 3 4 4 4 6% 21%	3526
	21st to end	Night	21% 23% 6% 11% 7% 3 4 4 4 5% 13%	5236

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	73% 8% 8% 8% 3	2281
	11th to 20th	Day	62% 5% 10% 18% 5%	2530
	21st to end	Day	73% 7% 7% 7% 6% 1	2783
February	1st to 10th	Day	58% 8% 13% 13% 8% 1	1510
	11th to 20th	Day	59% 6% 11% 15% 8% 1	1654
	21st to end	Day	64% 7% 7% 12% 9% 1	1480
March	1st to 10th	Day	53% 7% 10% 15% 13% 3	1800
	11th to 20th	Day	52% 7% 11% 18% 9% 2	1939
	21st to end	Day	53% 7% 11% 16% 11% 3	2240
April	1st to 10th	Day	59% 6% 10% 15% 9% 1	2160
	11th to 20th	Day	55% 6% 10% 19% 9% 1	2294
	21st to end	Day	51% 5% 9% 19% 13% 4	2340
May	1st to 10th	Day	50% 6% 14% 19% 8% 2	2340
	11th to 20th	Day	49% 5% 10% 23% 11% 1	2518
	21st to end	Day	46% 8% 13% 22% 8% 2	2919
June	1st to 10th	Day	49% 7% 13% 18% 12% 2	2700
	11th to 20th	Day	45% 7% 13% 22% 11% 1	2700
	21st to end	Day	45% 7% 15% 22% 10% 1	2700
July	1st to 10th	Day	39% 8% 16% 26% 10%	2626
	11th to 20th	Day	39% 8% 19% 26% 7% 1	2528
	21st to end	Day	43% 9% 16% 23% 8%	2591
August	1st to 10th	Day	46% 8% 19% 20% 7%	2466
	11th to 20th	Day	42% 6% 16% 27% 8%	2303
	21st to end	Day	46% 8% 16% 21% 8%	2573
September	1st to 10th	Day	48% 7% 15% 22% 9%	2134
	11th to 20th	Day	49% 8% 20% 20% 3	1980
	21st to end	Day	53% 8% 15% 18% 5%	1980
October	1st to 10th	Day	57% 6% 16% 16% 4	1940
	11th to 20th	Day	65% 8% 13% 12% 1	1675
	21st to end	Day	70% 7% 10% 9% 5%	1782
November	1st to 10th	Day	65% 8% 11% 13% 3	1672
	11th to 20th	Day	67% 8% 12% 9% 4	1562
	21st to end	Day	75% 9% 8% 6% 2 1	1359
December	1st to 10th	Day	67% 11% 10% 7% 4	1330
	11th to 20th	Day	63% 10% 11% 11% 4	1671
	21st to end	Day	74% 6% 9% 8% 3	2431
January	1st to 10th	Night	68% 6% 12% 10% 4	4674
	11th to 20th	Night	67% 6% 9% 15% 4	4440
	21st to end	Night	74% 6% 6% 9% 5%	4884
February	1st to 10th	Night	58% 8% 13% 13% 7%	2544
	11th to 20th	Night	60% 7% 11% 15% 6%	2201
	21st to end	Night	61% 5% 10% 15% 8% 1	1776
March	1st to 10th	Night	49% 6% 11% 18% 14% 1	2160
	11th to 20th	Night	50% 7% 13% 18% 12% 1	2021
	21st to end	Night	48% 8% 9% 20% 13% 3	2132
April	1st to 10th	Night	55% 6% 10% 17% 11% 1	1800
	11th to 20th	Night	51% 6% 10% 22% 10% 2	1614
	21st to end	Night	48% 5% 11% 19% 14% 3	1620
May	1st to 10th	Night	49% 6% 12% 21% 10% 2	1617
	11th to 20th	Night	49% 5% 9% 25% 11% 1	1382
	21st to end	Night	43% 7% 14% 21% 12% 3	1358
June	1st to 10th	Night	45% 6% 12% 23% 13% 2	1260
	11th to 20th	Night	46% 7% 13% 18% 15% 2	1260
	21st to end	Night	46% 7% 14% 24% 10%	1260
July	1st to 10th	Night	38% 8% 16% 25% 13%	1225
	11th to 20th	Night	43% 8% 15% 24% 11%	1307
	21st to end	Night	42% 7% 16% 25% 9%	1487
August	1st to 10th	Night	40% 7% 20% 23% 8%	1448
	11th to 20th	Night	34% 7% 22% 27% 9%	1598
	21st to end	Night	41% 7% 15% 26% 10% 1	1782
September	1st to 10th	Night	42% 8% 14% 24% 11% 1	1807
	11th to 20th	Night	45% 9% 16% 24% 5%	1980
	21st to end	Night	49% 8% 16% 21% 5%	1980
October	1st to 10th	Night	53% 8% 16% 18% 5%	2020
	11th to 20th	Night	59% 9% 15% 14% 4	2281
	21st to end	Night	67% 8% 10% 11% 4	2574
November	1st to 10th	Night	62% 7% 12% 14% 5%	2406
	11th to 20th	Night	67% 7% 11% 12% 3	2617
	21st to end	Night	73% 8% 9% 7% 3	2816
December	1st to 10th	Night	67% 9% 10% 10% 4	2850
	11th to 20th	Night	63% 9% 9% 13% 5% 2	3525
	21st to end	Night	72% 6% 8% 10% 3	5236

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	23% 19% 32% 16% 9%	202
	11th to 20th	Day	16% 15% 33% 27% 7% 1	270
	21st to end	Day	18% 18% 35% 22% 7%	297
February	1st to 10th	Day	20% 17% 37% 19% 5% 1	252
	11th to 20th	Day	23% 20% 36% 16% 5%	240
	21st to end	Day	23% 33% 33% 9% 1	198
March	1st to 10th	Day	16% 23% 41% 13% 7%	240
	11th to 20th	Day	23% 18% 32% 20% 5% 2	379
	21st to end	Day	21% 20% 31% 21% 6% 1	462
April	1st to 10th	Day	23% 15% 33% 22% 6% 1	420
	11th to 20th	Day	26% 18% 28% 15% 10% 2	412
	21st to end	Day	21% 21% 30% 18% 8% 2	420
May	1st to 10th	Day	21% 17% 30% 22% 8% 3	423
	11th to 20th	Day	19% 16% 34% 20% 8% 3	625
	21st to end	Day	22% 15% 34% 21% 6% 2	679
June	1st to 10th	Day	20% 13% 38% 22% 5% 2	630
	11th to 20th	Day	21% 13% 36% 18% 10% 2	630
	21st to end	Day	20% 13% 31% 22% 11% 3	630
July	1st to 10th	Day	14% 13% 38% 24% 10% 2	621
	11th to 20th	Day	16% 10% 35% 28% 8% 3	618
	21st to end	Day	17% 11% 31% 26% 11% 5%	684
August	1st to 10th	Day	16% 10% 33% 26% 12% 3	600
	11th to 20th	Day	17% 9% 23% 26% 19% 7%	439
	21st to end	Day	26% 9% 27% 20% 13% 5%	495
September	1st to 10th	Day	26% 11% 25% 20% 14% 4	450
	11th to 20th	Day	24% 14% 30% 23% 8% 2	450
	21st to end	Day	28% 11% 29% 20% 10% 1	450
October	1st to 10th	Day	26% 18% 27% 22% 7% 2	450
	11th to 20th	Day	32% 19% 28% 17% 4	325
	21st to end	Day	34% 18% 32% 11% 5%	297
November	1st to 10th	Day	29% 19% 32% 17% 2	270
	11th to 20th	Day	28% 26% 33% 12% 3	200
	21st to end	Day	34% 23% 28% 11% 4	180
December	1st to 10th	Day	28% 14% 33% 14% 10% 1	180
	11th to 20th	Day	24% 23% 37% 11% 5% 1	180
	21st to end	Day	31% 13% 32% 17% 5% 1	198
January	1st to 10th	Night	21% 13% 38% 21% 6%	950
	11th to 20th	Night	19% 15% 33% 25% 7% 1	950
	21st to end	Night	20% 13% 33% 27% 7% 1	1045
February	1st to 10th	Night	16% 12% 40% 25% 6%	884
	11th to 20th	Night	17% 13% 39% 21% 9% 1	703
	21st to end	Night	18% 16% 38% 22% 5%	592
March	1st to 10th	Night	14% 15% 35% 28% 7%	720
	11th to 20th	Night	18% 16% 36% 21% 7% 1	720
	21st to end	Night	15% 14% 35% 25% 10% 1	746
April	1st to 10th	Night	24% 14% 27% 27% 7% 1	540
	11th to 20th	Night	23% 12% 27% 28% 8% 1	533
	21st to end	Night	20% 11% 30% 27% 11% 1	540
May	1st to 10th	Night	19% 10% 26% 36% 7% 1	540
	11th to 20th	Night	22% 10% 26% 29% 11% 3	496
	21st to end	Night	21% 8% 31% 31% 8%	389
June	1st to 10th	Night	19% 8% 25% 38% 11%	360
	11th to 20th	Night	24% 8% 24% 34% 10%	360
	21st to end	Night	16% 8% 25% 35% 14% 1	360
July	1st to 10th	Night	12% 5% 29% 40% 13% 1	350
	11th to 20th	Night	17% 5% 25% 36% 17%	437
	21st to end	Night	18% 4 22% 36% 19% 1	591
August	1st to 10th	Night	15% 8% 19% 37% 20% 1	537
	11th to 20th	Night	13% 4 22% 35% 25% 2	534
	21st to end	Night	21% 6% 24% 32% 16% 2	594
September	1st to 10th	Night	19% 6% 27% 29% 16% 4	548
	11th to 20th	Night	22% 11% 27% 28% 12% 1	720
	21st to end	Night	27% 7% 26% 27% 12% 1	720
October	1st to 10th	Night	26% 13% 26% 25% 10%	720
	11th to 20th	Night	29% 13% 27% 23% 7% 1	720
	21st to end	Night	31% 15% 25% 23% 6%	792
November	1st to 10th	Night	26% 11% 35% 21% 5%	740
	11th to 20th	Night	29% 16% 28% 19% 8%	760
	21st to end	Night	30% 15% 30% 20% 5%	916
December	1st to 10th	Night	23% 16% 31% 21% 8% 1	950
	11th to 20th	Night	23% 17% 33% 19% 7% 1	950
	21st to end	Night	27% 17% 28% 21% 7% 1	1045

Page generated at 2024-02-02 05:20:27. Version ac07

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