Dinosaur Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dinosaur Provincial Park clear sky chart from 2005-11-06 to 2026-08-30.

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	7% 7% 3 7% 5% 5% 5% 4 6% 8% 42%	148674
	Night	6% 8% 3 9% 6% 5% 5% 4 6% 8% 38%	142270
Transparency	Day	39% 5% 15% 27% 12% 2	148371
	Night	42% 5% 15% 25% 11% 2	142157
Seeing	Day	11% 7% 25% 31% 19% 5%	17946
	Night	11% 7% 29% 36% 15% 2	26980

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 14% 6% 16% 9% 6% 6% 4 6% 7% 23%	4125
	11th to 20th	Day	4 8% 4 10% 7% 5% 8% 7% 7% 9% 31%	4119
	21st to end	Day	3 9% 4 9% 6% 5% 5% 4 7% 9% 40%	4965
February	1st to 10th	Day	8% 14% 5% 12% 7% 6% 6% 4 6% 8% 25%	1801
	11th to 20th	Day	7% 13% 5% 11% 7% 5% 6% 7% 8% 7% 24%	1845
	21st to end	Day	3 14% 4 11% 7% 6% 7% 4 6% 8% 28%	1571
March	1st to 10th	Day	4 8% 4 11% 7% 6% 5% 4 6% 9% 35%	4770
	11th to 20th	Day	5% 9% 4 9% 5% 5% 6% 5% 6% 8% 37%	5109
	21st to end	Day	7% 13% 5% 11% 6% 5% 5% 5% 7% 9% 27%	5607
April	1st to 10th	Day	8% 11% 3 9% 6% 6% 6% 4 6% 8% 34%	2574
	11th to 20th	Day	9% 11% 4 8% 5% 5% 5% 5% 6% 8% 34%	2700
	21st to end	Day	9% 9% 4 8% 6% 5% 5% 4 7% 8% 34%	2730
May	1st to 10th	Day	11% 8% 2 6% 4 4 5% 4 7% 7% 42%	8079
	11th to 20th	Day	10% 8% 3 8% 5% 6% 6% 5% 8% 10% 31%	8618
	21st to end	Day	10% 7% 2 7% 5% 5% 5% 4 6% 8% 41%	9649
June	1st to 10th	Day	13% 7% 3 7% 5% 5% 5% 4 7% 8% 37%	3150
	11th to 20th	Day	15% 7% 3 7% 6% 5% 6% 5% 7% 9% 32%	3150
	21st to end	Day	9% 4 1 6% 4 4 5% 5% 7% 10% 46%	3150
July	1st to 10th	Day	6% 3 1 4 3 3 4 4 6% 9% 56%	8820
	11th to 20th	Day	8% 5% 2 6% 4 4 5% 4 6% 8% 49%	8820
	21st to end	Day	5% 3 1 3 2 2 3 3 4 8% 66%	9569
August	1st to 10th	Day	5% 5% 2 5% 4 5% 4 4 6% 8% 52%	4605
	11th to 20th	Day	5% 3 2 5% 4 4 4 4 7% 10% 53%	4288
	21st to end	Day	7% 3 1 3 2 3 3 3 6% 8% 59%	4782
September	1st to 10th	Day	10% 5% 2 5% 3 3 4 3 5% 7% 53%	2490
	11th to 20th	Day	14% 6% 2 6% 4 4 3 2 5% 8% 47%	2220
	21st to end	Day	7% 6% 2 5% 4 3 4 4 6% 8% 51%	2200
October	1st to 10th	Day	6% 5% 3 8% 5% 5% 5% 5% 6% 6% 47%	3310
	11th to 20th	Day	5% 5% 3 5% 4 5% 5% 4 6% 9% 48%	3202
	21st to end	Day	8% 6% 2 6% 3 3 4 4 7% 8% 49%	3146
November	1st to 10th	Day	11% 13% 5% 9% 7% 6% 4 4 6% 7% 28%	1648
	11th to 20th	Day	6% 12% 4 9% 7% 6% 6% 4 6% 6% 35%	1680
	21st to end	Day	6% 12% 5% 10% 6% 6% 5% 4 6% 9% 32%	1535
December	1st to 10th	Day	9% 13% 4 9% 7% 6% 6% 6% 7% 8% 27%	2360
	11th to 20th	Day	7% 12% 5% 13% 7% 6% 6% 4 6% 7% 27%	2712
	21st to end	Day	3 8% 4 11% 6% 5% 6% 4 7% 7% 40%	3575
January	1st to 10th	Night	4 11% 5% 13% 9% 7% 6% 5% 7% 8% 24%	8768
	11th to 20th	Night	4 8% 4 10% 6% 5% 6% 4 6% 9% 37%	8779
	21st to end	Night	3 8% 4 10% 6% 5% 6% 4 6% 9% 37%	9259
February	1st to 10th	Night	6% 11% 4 10% 6% 6% 6% 5% 7% 8% 30%	2818
	11th to 20th	Night	6% 11% 4 11% 7% 6% 6% 5% 7% 7% 29%	2662
	21st to end	Night	4 10% 3 10% 6% 6% 6% 5% 8% 9% 33%	2233
March	1st to 10th	Night	3 7% 4 11% 6% 6% 6% 5% 7% 10% 35%	5331
	11th to 20th	Night	7% 8% 3 7% 5% 6% 6% 5% 9% 10% 35%	5110
	21st to end	Night	7% 15% 6% 13% 6% 7% 6% 5% 7% 8% 21%	5610
April	1st to 10th	Night	9% 11% 4 9% 6% 6% 6% 5% 6% 8% 31%	2044
	11th to 20th	Night	9% 11% 3 9% 6% 5% 5% 4 6% 8% 33%	1871
	21st to end	Night	9% 10% 3 6% 5% 4 6% 4 6% 9% 37%	1890
May	1st to 10th	Night	14% 8% 3 6% 4 4 5% 4 5% 7% 39%	4868
	11th to 20th	Night	10% 7% 3 8% 5% 6% 7% 5% 7% 10% 32%	4247
	21st to end	Night	11% 6% 2 8% 6% 6% 6% 5% 7% 8% 35%	4522
June	1st to 10th	Night	15% 8% 2 6% 4 5% 5% 5% 9% 8% 33%	1470
	11th to 20th	Night	14% 6% 3 5% 5% 6% 7% 6% 7% 9% 33%	1470
	21st to end	Night	8% 4 3 5% 4 5% 5% 4 7% 8% 47%	1470
July	1st to 10th	Night	4 3 1 4 3 3 5% 4 7% 8% 57%	4140
	11th to 20th	Night	7% 5% 2 6% 5% 4 5% 4 6% 9% 48%	4140
	21st to end	Night	4 3 2 4 4 3 4 3 5% 7% 60%	4499
August	1st to 10th	Night	6% 4 2 6% 4 5% 5% 4 7% 9% 48%	2765
	11th to 20th	Night	5% 4 2 6% 5% 5% 5% 5% 8% 10% 45%	2991
	21st to end	Night	9% 3 1 3 2 3 3 3 5% 9% 60%	3326
September	1st to 10th	Night	9% 5% 2 5% 5% 4 5% 3 5% 8% 49%	1909
	11th to 20th	Night	11% 5% 2 5% 4 4 3 3 5% 7% 51%	2176
	21st to end	Night	7% 5% 2 6% 5% 3 4 4 5% 8% 51%	2200
October	1st to 10th	Night	6% 6% 2 7% 4 4 4 4 6% 9% 49%	3880
	11th to 20th	Night	4 4 2 6% 5% 4 5% 5% 6% 9% 48%	3945
	21st to end	Night	5% 8% 4 8% 5% 4 5% 4 6% 8% 44%	4622
November	1st to 10th	Night	10% 11% 3 9% 6% 5% 5% 4 6% 7% 34%	2870
	11th to 20th	Night	5% 10% 2 9% 6% 6% 6% 4 7% 9% 36%	2940
	21st to end	Night	6% 11% 4 10% 6% 5% 5% 5% 7% 9% 31%	3082
December	1st to 10th	Night	6% 13% 5% 11% 7% 6% 6% 5% 7% 7% 27%	5040
	11th to 20th	Night	7% 12% 5% 11% 7% 6% 5% 5% 6% 9% 27%	5700
	21st to end	Night	4 7% 3 10% 6% 5% 5% 4 6% 7% 42%	7623

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	59% 5% 11% 18% 7%	4125
	11th to 20th	Day	48% 6% 15% 16% 14% 2	4140
	21st to end	Day	39% 6% 22% 27% 6%	4966
February	1st to 10th	Day	56% 6% 13% 18% 8%	1801
	11th to 20th	Day	51% 8% 13% 18% 9%	1854
	21st to end	Day	52% 6% 12% 21% 9%	1571
March	1st to 10th	Day	44% 5% 15% 24% 12%	4770
	11th to 20th	Day	45% 5% 16% 23% 12%	5110
	21st to end	Day	52% 7% 16% 19% 5%	5607
April	1st to 10th	Day	46% 7% 15% 22% 9%	2574
	11th to 20th	Day	46% 6% 12% 27% 7% 1	2700
	21st to end	Day	45% 7% 13% 26% 9% 1	2730
May	1st to 10th	Day	40% 4 10% 28% 14% 4	8079
	11th to 20th	Day	45% 6% 11% 26% 11%	8622
	21st to end	Day	39% 5% 11% 32% 12% 1	9650
June	1st to 10th	Day	44% 6% 14% 23% 11% 2	3150
	11th to 20th	Day	46% 7% 13% 24% 8% 1	3150
	21st to end	Day	31% 7% 20% 32% 9% 2	3150
July	1st to 10th	Day	25% 4 17% 33% 17% 4	8746
	11th to 20th	Day	34% 3 16% 27% 17% 4	8739
	21st to end	Day	20% 3 13% 30% 24% 10%	9362
August	1st to 10th	Day	30% 4 14% 35% 15% 2	4587
	11th to 20th	Day	27% 5% 19% 39% 10% 1	4327
	21st to end	Day	23% 4 17% 39% 16% 2	4781
September	1st to 10th	Day	31% 4 14% 28% 16% 7%	2490
	11th to 20th	Day	36% 5% 14% 29% 14% 2	2220
	21st to end	Day	30% 5% 15% 32% 15% 3	2200
October	1st to 10th	Day	37% 3 17% 32% 10% 1	3310
	11th to 20th	Day	32% 4 18% 32% 13% 1	3202
	21st to end	Day	32% 4 12% 39% 12% 1	3146
November	1st to 10th	Day	54% 5% 12% 20% 8% 1	1648
	11th to 20th	Day	46% 7% 17% 22% 7%	1680
	21st to end	Day	48% 6% 17% 21% 7% 1	1535
December	1st to 10th	Day	53% 6% 21% 16% 3 1	2360
	11th to 20th	Day	56% 5% 17% 18% 4	2714
	21st to end	Day	42% 4 12% 27% 13% 1	3575
January	1st to 10th	Night	55% 6% 14% 17% 8%	8769
	11th to 20th	Night	44% 4 18% 20% 14% 1	8820
	21st to end	Night	43% 5% 19% 25% 8%	9259
February	1st to 10th	Night	49% 7% 12% 20% 11% 1	2818
	11th to 20th	Night	50% 6% 12% 20% 12% 1	2663
	21st to end	Night	44% 7% 14% 24% 10% 1	2233
March	1st to 10th	Night	42% 5% 18% 26% 9%	5331
	11th to 20th	Night	40% 6% 16% 30% 8% 1	5110
	21st to end	Night	57% 8% 14% 15% 5%	5610
April	1st to 10th	Night	48% 6% 13% 21% 11% 1	2044
	11th to 20th	Night	48% 5% 12% 22% 12% 1	1871
	21st to end	Night	42% 6% 12% 26% 12% 1	1890
May	1st to 10th	Night	44% 4 6% 26% 17% 3	4866
	11th to 20th	Night	44% 6% 13% 24% 12% 1	4247
	21st to end	Night	42% 7% 12% 29% 9% 1	4526
June	1st to 10th	Night	44% 5% 16% 22% 12% 1	1470
	11th to 20th	Night	45% 8% 14% 22% 11% 1	1470
	21st to end	Night	33% 6% 16% 32% 12% 1	1470
July	1st to 10th	Night	24% 4 19% 31% 20% 2	4105
	11th to 20th	Night	34% 4 14% 29% 14% 5%	4098
	21st to end	Night	24% 4 10% 31% 19% 11%	4401
August	1st to 10th	Night	32% 5% 15% 29% 17% 2	2758
	11th to 20th	Night	32% 4 16% 34% 12% 2	3018
	21st to end	Night	23% 4 13% 37% 20% 3	3326
September	1st to 10th	Night	32% 5% 12% 26% 18% 7%	1909
	11th to 20th	Night	33% 5% 14% 30% 15% 4	2176
	21st to end	Night	30% 6% 13% 31% 18% 2	2200
October	1st to 10th	Night	33% 4 14% 33% 15% 1	3880
	11th to 20th	Night	32% 4 15% 31% 16% 2	3945
	21st to end	Night	38% 4 11% 37% 9% 1	4622
November	1st to 10th	Night	48% 6% 14% 21% 9% 1	2870
	11th to 20th	Night	43% 7% 18% 21% 10% 1	2940
	21st to end	Night	47% 7% 19% 19% 7% 1	3082
December	1st to 10th	Night	56% 5% 19% 16% 4	5040
	11th to 20th	Night	54% 6% 23% 14% 3	5697
	21st to end	Night	40% 5% 12% 25% 16% 2	7623

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	8% 8% 30% 30% 17% 7%	220
	11th to 20th	Day	12% 5% 29% 35% 16% 2	220
	21st to end	Day	4 7% 31% 36% 17% 4	242
February	1st to 10th	Day	16% 8% 28% 33% 13% 2	283
	11th to 20th	Day	11% 5% 22% 39% 18% 3	330
	21st to end	Day	8% 7% 27% 33% 20% 5%	287
March	1st to 10th	Day	10% 9% 31% 29% 15% 6%	540
	11th to 20th	Day	10% 8% 33% 32% 13% 4	540
	21st to end	Day	11% 9% 32% 27% 16% 4	594
April	1st to 10th	Day	10% 12% 29% 31% 14% 4	540
	11th to 20th	Day	12% 11% 31% 30% 14% 2	532
	21st to end	Day	13% 10% 24% 33% 15% 5%	540
May	1st to 10th	Day	14% 8% 21% 31% 19% 6%	699
	11th to 20th	Day	13% 8% 22% 33% 19% 6%	775
	21st to end	Day	16% 6% 19% 30% 22% 7%	844
June	1st to 10th	Day	13% 11% 21% 33% 19% 3	780
	11th to 20th	Day	16% 8% 29% 29% 16% 3	780
	21st to end	Day	11% 5% 22% 34% 21% 7%	780
July	1st to 10th	Day	8% 4 17% 37% 26% 8%	771
	11th to 20th	Day	10% 4 24% 32% 24% 6%	768
	21st to end	Day	6% 3 21% 32% 28% 9%	849
August	1st to 10th	Day	7% 5% 20% 35% 24% 9%	620
	11th to 20th	Day	8% 3 19% 33% 28% 10%	557
	21st to end	Day	7% 6% 21% 29% 25% 11%	620
September	1st to 10th	Day	12% 7% 22% 29% 24% 6%	530
	11th to 20th	Day	15% 6% 21% 29% 24% 5%	530
	21st to end	Day	12% 10% 33% 26% 16% 4	530
October	1st to 10th	Day	15% 4 24% 30% 19% 7%	357
	11th to 20th	Day	10% 8% 34% 24% 22% 2	330
	21st to end	Day	14% 12% 30% 28% 15% 1	363
November	1st to 10th	Day	18% 11% 28% 29% 13% 1	330
	11th to 20th	Day	12% 12% 37% 27% 10% 2	330
	21st to end	Day	8% 7% 39% 29% 11% 6%	253
December	1st to 10th	Day	12% 4 34% 31% 16% 3	220
	11th to 20th	Day	11% 12% 37% 28% 10% 2	220
	21st to end	Day	9% 8% 25% 35% 18% 5%	242
January	1st to 10th	Night	8% 9% 33% 34% 13% 1	1050
	11th to 20th	Night	13% 9% 31% 34% 12% 2	1050
	21st to end	Night	11% 8% 31% 35% 13% 2	1020
February	1st to 10th	Night	11% 8% 25% 37% 17% 2	840
	11th to 20th	Night	11% 7% 28% 40% 12% 1	824
	21st to end	Night	9% 6% 24% 37% 21% 4	692
March	1st to 10th	Night	7% 8% 31% 38% 13% 3	840
	11th to 20th	Night	10% 10% 31% 33% 14% 2	840
	21st to end	Night	14% 8% 27% 35% 15% 1	924
April	1st to 10th	Night	14% 10% 29% 32% 13% 3	689
	11th to 20th	Night	13% 8% 31% 36% 10% 1	623
	21st to end	Night	14% 7% 24% 37% 15% 1	630
May	1st to 10th	Night	16% 7% 23% 33% 18% 2	630
	11th to 20th	Night	11% 6% 28% 37% 17% 1	467
	21st to end	Night	20% 5% 20% 33% 20% 2	455
June	1st to 10th	Night	18% 8% 24% 32% 16% 2	420
	11th to 20th	Night	16% 6% 29% 33% 15% 1	420
	21st to end	Night	11% 6% 24% 36% 21% 2	420
July	1st to 10th	Night	7% 4 21% 46% 21% 1	410
	11th to 20th	Night	9% 4 26% 42% 18% 1	408
	21st to end	Night	4 5% 21% 44% 22% 3	460
August	1st to 10th	Night	9% 4 22% 41% 23% 2	511
	11th to 20th	Night	9% 4 20% 42% 24% 1	624
	21st to end	Night	11% 3 23% 39% 22% 2	687
September	1st to 10th	Night	12% 4 21% 45% 16% 2	600
	11th to 20th	Night	13% 4 21% 40% 19% 1	776
	21st to end	Night	11% 6% 30% 36% 15% 2	800
October	1st to 10th	Night	13% 5% 29% 39% 14% 2	800
	11th to 20th	Night	9% 8% 31% 35% 14% 2	800
	21st to end	Night	12% 10% 31% 36% 11%	890
November	1st to 10th	Night	17% 8% 33% 32% 8% 1	1025
	11th to 20th	Night	10% 11% 38% 29% 11% 2	1050
	21st to end	Night	10% 8% 32% 36% 12% 1	1050
December	1st to 10th	Night	12% 8% 31% 33% 13% 2	1050
	11th to 20th	Night	11% 8% 35% 32% 12% 2	1050
	21st to end	Night	10% 6% 33% 35% 14% 2	1155

Page generated at 2026-08-27 02:07:12. Version ac07

Copyright © 2026 Attilla Danko.