Whitemud Lake Gravel Pit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Whitemud Lake Gravel Pit clear sky chart from 2005-11-06 to 2024-11-25.

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	10% 9% 3 9% 6% 5% 5% 4 7% 8% 33%	106404
	Night	8% 9% 4 10% 6% 6% 6% 4 7% 8% 33%	101641
Transparency	Day	47% 5% 18% 23% 7%	106146
	Night	48% 4 17% 23% 8% 1	101545
Seeing	Day	14% 7% 27% 29% 17% 5%	16011
	Night	13% 6% 28% 35% 16% 2	24545

By Month

Percentage Cloud Cover NW (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	4 15% 7% 13% 10% 7% 6% 5% 7% 7% 20%	2219
	11th to 20th	Day	4 8% 4 10% 7% 6% 7% 9% 11% 10% 23%	2199
	21st to end	Day	6% 11% 5% 12% 6% 5% 6% 4 6% 8% 32%	2513
February	1st to 10th	Day	7% 13% 4 11% 9% 7% 8% 6% 7% 8% 21%	1520
	11th to 20th	Day	6% 11% 5% 14% 6% 6% 6% 5% 8% 7% 25%	1616
	21st to end	Day	4 13% 5% 9% 10% 8% 8% 6% 7% 8% 23%	1422
March	1st to 10th	Day	4 11% 5% 13% 8% 6% 7% 6% 6% 8% 25%	3138
	11th to 20th	Day	4 9% 4 11% 6% 5% 5% 4 7% 10% 34%	3486
	21st to end	Day	10% 14% 5% 15% 7% 5% 4 4 6% 7% 24%	3842
April	1st to 10th	Day	8% 13% 4 9% 7% 6% 5% 5% 5% 8% 29%	2408
	11th to 20th	Day	10% 12% 3 9% 7% 6% 5% 4 6% 8% 30%	2440
	21st to end	Day	11% 11% 4 10% 6% 6% 6% 5% 7% 7% 28%	2484
May	1st to 10th	Day	16% 9% 3 9% 6% 6% 5% 4 6% 6% 29%	4696
	11th to 20th	Day	14% 13% 3 7% 5% 5% 5% 4 6% 7% 30%	4694
	21st to end	Day	10% 10% 4 10% 7% 6% 6% 5% 7% 10% 27%	5161
June	1st to 10th	Day	15% 8% 3 8% 5% 6% 7% 5% 6% 7% 30%	2850
	11th to 20th	Day	20% 9% 4 8% 6% 5% 6% 4 7% 8% 23%	2989
	21st to end	Day	10% 7% 3 7% 5% 6% 6% 6% 7% 9% 34%	3040
July	1st to 10th	Day	8% 5% 2 6% 6% 5% 6% 5% 7% 9% 42%	4934
	11th to 20th	Day	9% 5% 2 6% 4 4 5% 4 7% 9% 45%	4740
	21st to end	Day	14% 6% 2 5% 4 4 4 4 6% 8% 42%	5138
August	1st to 10th	Day	13% 7% 2 6% 4 5% 4 4 6% 7% 43%	4635
	11th to 20th	Day	8% 6% 2 7% 5% 5% 5% 5% 7% 10% 41%	4147
	21st to end	Day	10% 6% 2 6% 4 4 5% 4 7% 9% 42%	4521
September	1st to 10th	Day	11% 8% 3 8% 4 4 4 4 6% 7% 41%	2441
	11th to 20th	Day	13% 8% 2 6% 5% 4 6% 3 7% 7% 39%	2090
	21st to end	Day	8% 7% 3 7% 5% 6% 5% 4 6% 8% 41%	2090
October	1st to 10th	Day	8% 11% 3 10% 5% 6% 4 4 6% 9% 35%	3244
	11th to 20th	Day	12% 11% 4 7% 4 4 5% 4 5% 8% 36%	2914
	21st to end	Day	8% 12% 5% 10% 6% 5% 4 4 6% 6% 32%	2978
November	1st to 10th	Day	10% 13% 6% 10% 7% 5% 6% 4 6% 7% 26%	1568
	11th to 20th	Day	7% 12% 4 14% 7% 6% 6% 4 6% 8% 27%	1435
	21st to end	Day	5% 12% 4 14% 8% 5% 5% 4 6% 8% 28%	1358
December	1st to 10th	Day	5% 11% 5% 11% 8% 8% 8% 7% 8% 7% 23%	1330
	11th to 20th	Day	9% 10% 4 11% 7% 8% 6% 5% 8% 7% 26%	1682
	21st to end	Day	3 6% 3 9% 6% 6% 6% 5% 8% 9% 38%	2442
January	1st to 10th	Night	4 12% 6% 18% 9% 7% 6% 6% 6% 6% 20%	4726
	11th to 20th	Night	3 8% 4 10% 8% 7% 8% 7% 6% 6% 34%	4699
	21st to end	Night	6% 12% 4 11% 8% 6% 5% 4 7% 8% 29%	5173
February	1st to 10th	Night	6% 12% 4 11% 8% 7% 8% 5% 7% 7% 25%	2660
	11th to 20th	Night	6% 11% 4 11% 7% 7% 7% 4 6% 7% 30%	2450
	21st to end	Night	3 9% 3 9% 8% 8% 6% 7% 8% 8% 31%	2032
March	1st to 10th	Night	3 11% 6% 12% 7% 6% 6% 5% 9% 10% 27%	3736
	11th to 20th	Night	5% 8% 4 10% 5% 6% 5% 4 7% 9% 37%	3492
	21st to end	Night	7% 12% 6% 15% 7% 6% 5% 5% 6% 7% 23%	3808
April	1st to 10th	Night	7% 10% 4 8% 7% 6% 6% 5% 6% 8% 33%	1772
	11th to 20th	Night	8% 10% 3 9% 7% 5% 7% 4 7% 7% 32%	1691
	21st to end	Night	10% 11% 3 8% 4 5% 6% 4 7% 7% 34%	1696
May	1st to 10th	Night	18% 9% 3 8% 5% 5% 4 4 6% 7% 30%	2262
	11th to 20th	Night	15% 11% 2 8% 5% 5% 5% 4 6% 8% 33%	2199
	21st to end	Night	12% 8% 2 7% 6% 5% 6% 5% 8% 10% 29%	2414
June	1st to 10th	Night	16% 7% 3 9% 7% 5% 4 4 6% 7% 32%	1330
	11th to 20th	Night	16% 9% 2 7% 6% 5% 5% 6% 7% 10% 26%	1187
	21st to end	Night	10% 6% 3 7% 5% 5% 4 4 6% 6% 41%	1140
July	1st to 10th	Night	8% 5% 2 6% 5% 5% 4 3 7% 8% 47%	2023
	11th to 20th	Night	6% 5% 2 6% 5% 5% 5% 5% 7% 9% 45%	2220
	21st to end	Night	14% 6% 2 5% 3 3 4 4 6% 8% 45%	2414
August	1st to 10th	Night	10% 6% 2 6% 5% 4 6% 3 7% 7% 44%	2294
	11th to 20th	Night	10% 7% 3 7% 5% 5% 5% 4 7% 8% 40%	2687
	21st to end	Night	11% 6% 2 6% 4 4 5% 4 6% 7% 45%	3146
September	1st to 10th	Night	13% 6% 3 6% 4 3 4 4 5% 8% 45%	1737
	11th to 20th	Night	12% 6% 2 6% 4 3 3 3 5% 9% 46%	2090
	21st to end	Night	8% 6% 2 6% 5% 4 5% 4 6% 8% 44%	2090
October	1st to 10th	Night	7% 7% 3 9% 6% 5% 6% 3 7% 9% 38%	3728
	11th to 20th	Night	9% 8% 3 8% 5% 5% 6% 4 7% 9% 37%	4013
	21st to end	Night	8% 8% 4 10% 5% 5% 6% 5% 8% 8% 32%	4548
November	1st to 10th	Night	12% 14% 6% 10% 8% 5% 4 4 5% 6% 27%	2730
	11th to 20th	Night	7% 13% 5% 12% 8% 6% 6% 4 6% 7% 24%	2963
	21st to end	Night	5% 11% 5% 14% 9% 6% 5% 4 7% 7% 27%	2917
December	1st to 10th	Night	7% 12% 5% 11% 7% 6% 5% 4 7% 8% 28%	2850
	11th to 20th	Night	7% 13% 5% 13% 9% 7% 5% 5% 7% 7% 22%	3510
	21st to end	Night	3 7% 3 8% 6% 6% 7% 4 7% 9% 40%	5214

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	63% 3 13% 16% 5% 1	2219
	11th to 20th	Day	51% 4 15% 17% 13% 1	2220
	21st to end	Day	50% 3 21% 18% 8%	2513
February	1st to 10th	Day	59% 4 12% 16% 8%	1520
	11th to 20th	Day	54% 4 16% 17% 8%	1625
	21st to end	Day	54% 6% 14% 19% 7%	1422
March	1st to 10th	Day	54% 4 17% 20% 5%	3138
	11th to 20th	Day	46% 4 21% 21% 7%	3487
	21st to end	Day	57% 5% 13% 21% 4	3842
April	1st to 10th	Day	52% 5% 15% 19% 8% 1	2408
	11th to 20th	Day	51% 4 12% 23% 10%	2440
	21st to end	Day	52% 5% 12% 23% 8% 1	2484
May	1st to 10th	Day	52% 5% 10% 25% 8%	4696
	11th to 20th	Day	50% 6% 9% 25% 10% 1	4698
	21st to end	Day	50% 6% 19% 17% 8%	5162
June	1st to 10th	Day	51% 4 15% 22% 8%	2850
	11th to 20th	Day	58% 5% 14% 19% 5%	2989
	21st to end	Day	45% 6% 19% 23% 7% 1	3040
July	1st to 10th	Day	36% 6% 21% 29% 8% 1	4858
	11th to 20th	Day	34% 5% 20% 29% 13% 1	4659
	21st to end	Day	39% 5% 23% 27% 6%	4976
August	1st to 10th	Day	39% 5% 22% 32% 2	4617
	11th to 20th	Day	37% 6% 25% 25% 7%	4189
	21st to end	Day	37% 5% 31% 24% 3	4520
September	1st to 10th	Day	42% 4 19% 26% 8% 1	2441
	11th to 20th	Day	44% 3 20% 27% 6%	2090
	21st to end	Day	40% 5% 19% 25% 10% 2	2090
October	1st to 10th	Day	46% 3 23% 24% 4	3244
	11th to 20th	Day	46% 3 15% 28% 7%	2914
	21st to end	Day	51% 4 18% 24% 3	2978
November	1st to 10th	Day	56% 4 14% 19% 6%	1568
	11th to 20th	Day	54% 5% 19% 18% 4	1435
	21st to end	Day	54% 5% 16% 19% 5% 1	1358
December	1st to 10th	Day	55% 5% 14% 18% 8% 1	1330
	11th to 20th	Day	55% 4 15% 20% 6%	1684
	21st to end	Day	42% 3 11% 31% 12% 1	2442
January	1st to 10th	Night	64% 3 11% 15% 6% 1	4726
	11th to 20th	Night	49% 4 13% 21% 12% 1	4740
	21st to end	Night	53% 3 22% 16% 6%	5173
February	1st to 10th	Night	55% 4 13% 19% 8% 1	2660
	11th to 20th	Night	53% 4 13% 19% 10% 1	2451
	21st to end	Night	46% 5% 14% 24% 10% 1	2032
March	1st to 10th	Night	50% 4 16% 24% 6%	3736
	11th to 20th	Night	42% 4 21% 22% 9% 1	3492
	21st to end	Night	57% 4 14% 19% 6%	3808
April	1st to 10th	Night	47% 4 13% 22% 13% 1	1772
	11th to 20th	Night	50% 3 11% 22% 12% 2	1691
	21st to end	Night	47% 4 12% 23% 13% 1	1696
May	1st to 10th	Night	52% 3 9% 25% 10% 1	2262
	11th to 20th	Night	49% 3 10% 26% 10% 1	2199
	21st to end	Night	48% 4 19% 20% 8% 1	2414
June	1st to 10th	Night	50% 3 13% 23% 10% 1	1330
	11th to 20th	Night	51% 6% 18% 19% 6%	1187
	21st to end	Night	41% 4 22% 25% 6% 1	1140
July	1st to 10th	Night	35% 6% 21% 25% 13% 1	1990
	11th to 20th	Night	33% 5% 19% 34% 8% 1	2178
	21st to end	Night	36% 4 23% 29% 7%	2337
August	1st to 10th	Night	38% 5% 21% 34% 2	2287
	11th to 20th	Night	40% 6% 21% 24% 8%	2711
	21st to end	Night	37% 4 25% 29% 5%	3146
September	1st to 10th	Night	39% 3 21% 28% 8% 2	1737
	11th to 20th	Night	37% 2 19% 31% 10% 1	2090
	21st to end	Night	38% 4 16% 28% 12% 2	2090
October	1st to 10th	Night	40% 4 21% 27% 7%	3728
	11th to 20th	Night	43% 3 16% 32% 6%	4013
	21st to end	Night	46% 5% 22% 21% 5%	4548
November	1st to 10th	Night	58% 3 11% 22% 5%	2730
	11th to 20th	Night	57% 6% 14% 17% 5%	2963
	21st to end	Night	55% 4 18% 18% 4 1	2917
December	1st to 10th	Night	54% 4 12% 20% 9% 1	2850
	11th to 20th	Night	60% 4 14% 15% 6%	3507
	21st to end	Night	40% 3 17% 22% 16% 2	5214

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	9% 4 36% 26% 19% 5%	180
	11th to 20th	Day	9% 8% 34% 28% 14% 6%	180
	21st to end	Day	10% 9% 36% 32% 9% 4	198
February	1st to 10th	Day	13% 8% 39% 27% 11% 2	180
	11th to 20th	Day	12% 6% 31% 29% 19% 3	247
	21st to end	Day	6% 10% 34% 29% 16% 5%	234
March	1st to 10th	Day	10% 10% 33% 30% 13% 2	460
	11th to 20th	Day	11% 8% 36% 29% 12% 5%	460
	21st to end	Day	18% 6% 30% 30% 14% 2	506
April	1st to 10th	Day	11% 11% 38% 25% 12% 3	460
	11th to 20th	Day	16% 8% 28% 33% 12% 4	452
	21st to end	Day	18% 10% 31% 27% 12% 2	474
May	1st to 10th	Day	15% 11% 23% 27% 19% 4	653
	11th to 20th	Day	13% 7% 25% 31% 18% 6%	675
	21st to end	Day	18% 6% 21% 28% 20% 7%	734
June	1st to 10th	Day	18% 7% 28% 32% 12% 3	680
	11th to 20th	Day	22% 6% 20% 26% 21% 6%	819
	21st to end	Day	12% 6% 18% 32% 24% 9%	870
July	1st to 10th	Day	14% 3 17% 34% 23% 9%	785
	11th to 20th	Day	13% 6% 19% 30% 23% 9%	668
	21st to end	Day	10% 4 19% 31% 27% 9%	739
August	1st to 10th	Day	15% 3 16% 31% 23% 11%	630
	11th to 20th	Day	10% 5% 28% 31% 21% 5%	477
	21st to end	Day	14% 6% 24% 30% 19% 7%	539
September	1st to 10th	Day	18% 9% 29% 22% 16% 6%	490
	11th to 20th	Day	19% 9% 26% 29% 15% 2	490
	21st to end	Day	12% 14% 31% 26% 14% 3	490
October	1st to 10th	Day	16% 9% 27% 30% 16% 3	348
	11th to 20th	Day	18% 7% 37% 28% 10% 1	300
	21st to end	Day	21% 11% 35% 20% 11% 3	330
November	1st to 10th	Day	17% 7% 32% 33% 8% 3	300
	11th to 20th	Day	12% 9% 45% 24% 9% 2	217
	21st to end	Day	9% 9% 39% 28% 12% 4	188
December	1st to 10th	Day	11% 7% 38% 25% 14% 5%	180
	11th to 20th	Day	13% 7% 38% 32% 8% 2	180
	21st to end	Day	9% 4 30% 31% 19% 7%	198
January	1st to 10th	Night	13% 7% 33% 34% 12% 2	950
	11th to 20th	Night	10% 6% 35% 36% 12% 1	950
	21st to end	Night	13% 9% 37% 30% 9% 2	1017
February	1st to 10th	Night	11% 8% 28% 33% 17% 3	760
	11th to 20th	Night	10% 5% 30% 39% 15% 1	744
	21st to end	Night	7% 4 30% 37% 20% 3	628
March	1st to 10th	Night	9% 6% 30% 39% 13% 3	760
	11th to 20th	Night	12% 6% 30% 36% 15% 2	760
	21st to end	Night	15% 5% 27% 36% 15% 3	836
April	1st to 10th	Night	13% 5% 27% 35% 17% 4	632
	11th to 20th	Night	13% 6% 28% 37% 14% 2	563
	21st to end	Night	17% 6% 24% 34% 18% 2	570
May	1st to 10th	Night	14% 6% 22% 36% 19% 4	409
	11th to 20th	Night	15% 5% 21% 38% 20% 2	374
	21st to end	Night	18% 6% 17% 33% 25% 2	411
June	1st to 10th	Night	17% 6% 18% 39% 17% 2	380
	11th to 20th	Night	20% 3 18% 34% 22% 3	380
	21st to end	Night	13% 2 17% 40% 24% 4	380
July	1st to 10th	Night	14% 2 16% 42% 25% 1	370
	11th to 20th	Night	11% 4 20% 41% 22% 2	368
	21st to end	Night	12% 4 15% 38% 27% 5%	416
August	1st to 10th	Night	9% 3 15% 35% 31% 7%	378
	11th to 20th	Night	10% 4 20% 38% 26% 3	488
	21st to end	Night	15% 4 21% 37% 23% 1	627
September	1st to 10th	Night	16% 5% 20% 32% 25% 2	570
	11th to 20th	Night	15% 5% 18% 42% 18% 2	760
	21st to end	Night	13% 6% 28% 36% 16% 1	760
October	1st to 10th	Night	14% 4 29% 36% 15% 2	760
	11th to 20th	Night	13% 5% 34% 35% 12% 3	760
	21st to end	Night	15% 8% 33% 31% 13% 1	891
November	1st to 10th	Night	19% 6% 30% 31% 12% 2	975
	11th to 20th	Night	14% 8% 35% 30% 11% 3	1000
	21st to end	Night	10% 6% 40% 32% 10% 2	973
December	1st to 10th	Night	13% 7% 33% 30% 13% 3	950
	11th to 20th	Night	11% 8% 35% 33% 12% 1	950
	21st to end	Night	10% 5% 32% 34% 16% 3	1045

Page generated at 2024-11-22 06:02:29. Version ac07

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